Did a few more hours last night and I really didn't want to stop playing so I suppose that's a good sign.
It reminds me of Mad Max, Sleeping Dogs and of course, the obvious one GTA.
The story has been very good, and the characters interesting. The gunplay is very solid and extremely satisfylng, as is some of the stealth based combat which can lead to some extremely graphic executions.
Regarding performance, I haven't noticed any real issues apart from some occasional pop-up and dull textures. I've never really been one to judge games on graphics or FPS though, I tend to concentrate more on the gameplay and immersion.
I'd give it around the 8/10 mark at the moment, but I do feel as though i've only scratched the surface so it could go either way.