I dunno, I use Deep Research from Claude, ChatGPT, and Gemini, and Gemini is the only one that ignores my requests and always produces the most inane high school student wannabe management consultant "report" with introduction and restatement of the problem and background and all that. Its "voice" (the prose, I mean, not text to speech) is so irritating I've stopped using it.

The other ones will do the thing I want: search a bunch, digest the results, and give me a quick summary table or something.

Gemini is high on hallucination. When I ask it about my own software it not only changes my own name to a similar one common in my language but also makes up stuff about our team saying some stranger works with us (he works in the same niche but that's about it).

It's annoying when it's so confident making up nonsense.

Imo Chat GPT is just a league above when it comes to reliability.

I like Gemini Deep Research because ChatGPT's has very low limits, but it is extremely on rails. Yesterday as an experiment I asked it to do a bunch of math rather than write a report, and it did the math but then wrote a report scolding me for not appreciating the beauty of the humanities.

Suppose it depends. I think of it like this article suggests. It is very good at searching and scraping a lot of websites fast. And then summarizing that some.