Gemini, ChatGPT and Claude these are the most widely adopted LLMs which are quite general purpose. But they also have nuanced quirks and preferences for certain tasks.
Deep Research is a big deal and it has helped me learn a new concept every day. I use Grok AI, Gemini AI, Chat GPT and even mistral ai for specific things.
Hallucinations are no longer a big deal in AI, they have reduced considerably over the years. It is still a problem but not what it used to be.