I use it all the time for work. Not much for actual code that goes into production, but a lot for "tell me what this does" or "given x, how do I do y". It speeds me up a ton. I'll also have it do code review when I'm uncertain about something, asking if there's any bugs or inefficiencies in a given chunk of code. I've actually found it to be more reliable about code than more general topics. Though I'm using it in a fairly specific way with code, versus asking for deep information about history for example, where is frequently gets facts very wrong.