Compared to Claude and Gemini, I think ChatGPT is really more thorough when it comes to web searches and providing sources. The others usually answer in a short paragraph and give me maybe one or two sources, while ChatGPT thinks for a minute and presents me a little mini report with 10-20 sources to look further into. This is honestly the reason why I stopped paying for Kagi, but I'm not sure how worse this will get when ads become commonplace in ChatGPT.