I use Copilot fully integrated with Office 365 in my work, and was one of the beta testers back in November. Anecdotally, it’s no better than any other LLM, and I have found hallucinates significantly more than ChatGPT. The Office integration is useful and I do use it more than any other AI tool for its convenience being ‘inside’ of Excel / Outlook etc, but you aren’t missing much by not having it.