Well, I'm playing on a medium spec PC and so far (40 hours) I have indeed encountered some bugs, but they are very minor none of them have much effect on gameplay. With that out of the way, the story and gameplay are amazing 10/10. I thought the story (until now, I haven't completed it yet) was better than Witcher 3 main quest, but Witcher 3 has better romance (Yennefer is the best), though Cyberpunk also has very good romance. Night city itself looks amazing, and soundtrack is as good as Witcher 3. I specially like the radio option while driving (you can select your genre by switching radio channels).
Melee combat style is same as Witcher 3 (replacing Quen and signs with time slowing abilities etc), but the addition of guns, grenades, stealth etc., with quick switch between guns and swords etc. make the overall combat much more versatile and fun. One complain I have is that there is no way to reset your build yet (maybe they'll add it later), but by end game the players would have maxed out attributes for multiple play styles so I guess that's not too important.