For me the biggest gripe is that I cannot configure it as I want and that it assumes I'm computer-illiterate. On top of that a lot of the approaches chosen by Apple regarding e.g. the UI are simply counterintuitive to me.

I still prefer it to Windows but (at least for me) it is inferior to a properly setup Linux box with stuff like a titling WM. But if I would to recommend someone a computer just for browsing, email, etc. then a Mac would be my top choice.