I've had a bit of a go, is very impressive-looking and quite atmospheric but I'm very early-game still. Haven't come across any terrible bugs but the odd one or two, and my in-game partner walked straight over a corpse and caused comical ragdoll flipping about from the body. 

The streets are impressive to look at if you've high-end hardware, lots of people milling around and doing stuff. On the other hand it doesn't take that much to break immersion, it's not like every NPC has convincing AI to react if you start doing something unexpected. I get the impression it's a game where you're best following the missions 'properly' rather than dicking about looking for emergent opportunities. There's bloody loads of missions though so that shouldn't be too big a problem.
I've got quite a few other things going on at the moment so I'm tempted to park it while they fix more bugs. Witcher 3 was evidently much the same, a buggy release eventually patched into a finished gem.

From what I've read, it's the consoles that have had the most problems, not so much decent gaming pcs. At any rate far above my specs, so won't be trying it anytime soon.

"comical ragdoll flipping about from the body"

I encounter that with some frequency in FC5, particularly when vehicles are involved, but sometimes corpses half-sticking out of rocks.

I had major high hopes because i loved Witcher 3 so much. Its a good game for what it is. I mean i guess I'm more of a mages and monsters kind of girl, but will keep playing through. I can't help but wonder if the disappointing reviews have more to do with expectations than the game. But then, I'm playing PC so haven't run into any game breaking bugs yet. My friend playing on PS5 has.