Grok, in my experience, is extremely prone to hallucinations when not used for coding. It will readily claim to have access to internal Slack channels at companies, it will hallucinate scientific papers that do not exist, etc. to back its claims.

I don’t know if the hallucinations extend to code, but it makes me unwilling to consider using it.

Fair - it's gotten significantly better over the last 4 months or so, and hallucinations aren't nearly as bad as they once were. When I was using Heavy, it was excellent at ensuring grounding and factual statements, but it's not worth $100 more than ChatGPT Pro in capabilities or utility. In general, it's about the same as ChatGPT Pro - once every so often I'll have to call out the model making something up, but for the most part they're good at using search tools and ensuring claims get grounding and confirmation.

I do expect them to pull ahead, given the resources and the allocation of developers at xAI, so maybe at some point it'll be clearly worth paying $300 a month compared to the prices of other flagships. For now, private hosts and ChatGPT Pro are the best bang for your buck.