Big thumbs up for Cyberpunk 2020/Interlock. It is incredibly easy to adapt that system to whatever game you want to run. It does grit like no other system I've ever seen and has intuitive advancement mechanics. Its also possible just to slap together some pathetic gangers and have a shootout in some convenience store, and have an amazing afternoon of fun.
Just avoid the Cybergeneration book and its various supplements like the plague.
I cant get my group into that, yet. We are definitely playing Cyberpunk 2077 when it comes out (whether they like it or not.And they will like it) but at the moment 2020 is looking too aged and complex to get my group into it. I'd prefer to use adventures or sourcebooks from it and ran a different system, a light one. Technoir seemed like a good candidate but its too alien with its tags and word system and what not.