Comparing Popular Generative AI Search Engines

Key Points

AI platforms are reshaping search as large language models transform how people discover information, shifting from static results to AI-driven experiences.
Google’s AI Overviews and AI Mode, plus ChatGPT and Perplexity are disrupting visibility, discoverability, and brand reputation.
The shift creates new opportunities and risks for brands. Leaders need a comprehensive guide to the platforms that matter in 2025.

The rise of AI search

Organic search is undergoing its biggest transformation since Google became a household name, driven by the large language models (LLMs) that power AI.

Search’s evolution toward AI-driven conversational experiences has altered how people find information and engage with brands online. Google has adapted, rolling out AI-generated elements like AI Overviews and AI Mode. For brands and leaders, this change is disrupting discoverability, visibility, perception, and brand reputations.

Here’s a guide to the AI platforms that can make or break your reputation in the AI search era.

Google AI search (Gemini, AI Mode, and AI Overviews)

Google remains the dominant global search engine and is growing through the AI revolution, partly because it is the information retrieval source for most AI tools and platforms. LLMs rely on it.

Google is casting AI as the star of the new search, which combines AI and organic results in a single venue, unlike walled-off competitors.

Let’s start with Gemini.

What is Google Gemini?

Google’s Gemini is a multimodal LLM and chatbot capable of processing and generating text, images, audio, video, and code. It’s Google’s AI brain that powers Google’s AI products and tools, including AI Overviews, which appears in traditional Google Search, and AI Mode, which is a parallel experience.

What models are available?

There are currently three Gemini 2.5 models available for users: Flash-Lite, Flash, and Pro.

Flash-Lite is an efficiency-focused, lower-cost option.
Flash is for fast conversational interactions and serves as the platform’s flagship tier.
Pro is for advanced reasoning tasks. It’s well-suited for coding, mathematics, and scientific problem-solving.

Where does Gemini source its answers from?

Google Gemini relies on multiple sources and contexts:

Its training data: A massive dataset comprising text, images, code, and other material from books, websites, and licensed content that Gemini learns from continuously.
Live web content: Gemini can use Google Search and make use of the latest news, product info, and anything else from live URLs.
The context you provide: Gemini can use the text, files, or data you give it to perform requested tasks. For example, summarizing a Google Doc, drafting a reply based on an email thread, or finding recipes based on what’s in your fridge.

How much does Gemini cost?

Free (Standard) — Gemini 2.5 Flash, unlimited basic AI chats, web-connected answers, and built-in help across Google apps.
AI Pro (Individual) — $19.99/month or $199.99/year — Gemini 2.5 Pro, Flow (AI video), Whisk (image-to-video), Deep Research, Jules (coding), NotebookLM, Workspace integration, 2 TB storage, 1,000 monthly AI credits, and Google Store cashback.
AI Ultra — $249.99/month (intro $124.99 for first 3 months) — All Pro features plus Gemini 2.5 Deep Think, Veo 3 video, max usage limits, Project Mariner agent, 30 TB storage, and YouTube Premium.

What is AI Overviews (AIO)?

AI Overviews (AIO) is a Google Search feature that generates detailed, sourced, conversational answers to user Google searches.

AI Overviews’ answers automatically appear above organic results, pushing the blue links farther down the search engine results page (SERP). Even if your content or site ranks first, the AIO summary can obscure it.

How does Google decide what gets included in AI Overviews?

Google is not transparent about how Gemini prioritizes data. We do know that AI Overviews uses a mix of relevance, authority, and clarity as inclusion factors. SEO performance can contribute to inclusion in AIOs. Our research proves it.

AI Overviews doesn’t just pull the highest-ranked organic result. It builds the best possible answer by searching, combining sources, generating an answer, then layering citations and logical next queries.

What is AI Mode?

AI Mode is an optional feature that is essentially a traditional search replacer. Instead of taking up minimal real estate in the SERPs like AI Overviews, it’s a full-page, AI-first search experience without the SERPs.

AI Mode also uses a query fan-out feature that breaks user questions into subtopics. It simultaneously searches, supporting the next step in the user’s online journey. It empowers users to ask follow-up questions and explore without leaving the interface.

AI Overviews vs AI Mode

AI Overviews	AI Mode
Answers user searches with summarized information in the main Google Search results page, usually blending multiple sources.	Research mode that fans out queries, gathers fresh web information, and presents a richer answer with room for exploration.

Perplexity.ai

Perplexity positions itself as a trusted answer engine, focusing on robust features for detailed research. It’s similar to other conversational search engines but is slightly more niche.

Where does Perplexity source its answers from?

Perplexity scans the web for authoritative information and distills it into clear, concise summaries. It leverages LLMs, including its own Sonar family and R1-1776 models, along with external models such as GPT-5, Claude 4.0 Sonnet/Opus, and Gemini 2.5 Pro.

Every answer is a blend of fresh web results backed by advanced AI model reasoning power. Pro users have access to premium LLMs and enhanced features that expand how information is refined and presented.

How much does Perplexity cost?

Free (Standard) — Unlimited basic searches, a limited number of Pro searches per day, standard AI model access, and citations included.
Pro (Individual) — $20/month or $200/year — Includes premium model access (e.g., GPT-4.1, Claude 4.0 Sonnet, Mistral), Comet Plus, expanded usage, API access, image generation, and limited AI video generation capabilities.
Enterprise Pro — $40/month per user (or $400/year) — Adds team features like seat management, file repository, SSO, audit logs, and admin controls.
Max — $200/month — Encompasses all Pro features plus unlimited model and Labs access, early Comet browser availability, priority support, and early/new product access.

Growing user base and brand visibility potential

Perplexity adoption is rapidly expanding among everyday users and professionals. Aravind Srinivas, co-founder and CEO of Perplexity, recently shared that the company handled 780 million queries in May 2025 — a surge that marked more than 20% month-over-month growth.

Perplexity also launched an AI-powered web browser called Comet, as well as a subscription called Comet Plus. Directly challenging Google Chrome is a bold move. It signals the company’s ambition to redefine how users interact with the web.

For brands, Perplexity inclusion can reach audiences at moments of active research, when credibility and trust are most important. In other words, it can influence decision-making.

ChatGPT (OpenAI)

ChatGPT is OpenAI’s conversational AI platform that allows users to ask questions and interact with LLMs in a chat interface. It’s designed to handle casual queries and professional tasks.

Where does ChatGPT source its answers from?

ChatGPT relies on the multimodal large language model GPT‑5, likely trained on a mixture of licensed data, publicly available data, and data created by human trainers.

On the Plus, Pro, and Team plans, ChatGPT can browse the web in real time. With Agent Mode, it can go further: autonomously completing complex, multi-step tasks using its own secure virtual computer environment.

How much does ChatGPT cost?

Free: Access to GPT-5 with usage limits, basic memory features, and limited file/image uploads. Standard response speeds.
Plus: $20/month — Priority access, faster responses, and access to advanced models like GPT-5, with improved reasoning and content generation tools.
Pro: $200/month — Higher usage limits with advanced models (e.g., GPT-5 Pro, o1-pro), early access to new features, stronger reasoning capabilities, and access to emerging agent-style tools.
Team: ~$30/user/month (or ~$25 with annual billing) — Collaboration tools, shared workspaces, admin management, and team-level usage controls.
Enterprise: Custom pricing (~$60/user/month typical) — Enterprise-grade security, SOC-2 compliance, SSO, advanced admin controls, and unlimited high-tier model access.

What are ChatGPT’s unique features?

ChatGPT stands out for its distinct personality and assistant-style approach, which emphasize solving problems with relevant solutions and offering a human-like personality. Paid tier users can design their own unique GPTs for different purposes.

ChatGPT also can remember what you tell it, reference older conversations, and build a sophisticated understanding of the user.

Audience and behavior: Who uses these platforms?

While specific demographics aren’t publicly available, each tool offers something for everyone, from unintentional Google users who stumble into AI Overviews to experienced power users.

Here are some takeaways to help you prioritize platform-specific strategies and maximize influence across AI-driven search environments:

Google Gemini and AI Mode are integrated into users’ daily search behavior, making them key touchpoints for brands seeking visibility in routine search moments.
AI Overviews shapes perception before users even click anything. AIOs integrated into traditional Google Search are subtly suffusing everyday search experiences with AI. This has made AI search the new normal for Google users.
Perplexity attracts research-heavy users who are exploring topics in depth. It presents an opportunity for brands to influence the most engaged audiences in decision moments.
ChatGPT‘s conversation-based exploration and ideation enable brands that are cited in its answers to connect with users in an interactive, intent-matched manner.

Recommendations for brands and leaders

There isn’t a clear winner in the space yet, though data indicates that Google still leads. We predicted a few potential situations. Either way, adoption is rapidly increasing and brands need to act.

Start by auditing your brand in the top AI search tools, with attention to brand mentions, citations and sources, and sentiment. With this data, you can build an online reputation strategy that complements your other spends and prioritizes the assets and AI platforms that offer the biggest reputation and visibility wins.

Brands must recognize the AI search-driven opportunities and risks. It’s time to influence the narrative in the AI search platforms your audiences rely upon.