I have an R4 - and it is a very nice case. It's very easy to build in, it can be a quiet case, and the cooling is great. The only problem I had was threading some of the standoffs - I had to use pliers to put some in, but other than that, had no problems.
I transferred all the fans from my old case - I have 2x140mm intake (front), 2x140mm exhaust (top), 120mm rear exhaust. CPU temps are in the high 20's idle with an Arctic Freezer 7 Pro Rev.2 on a i5 4670. GPU temps are also in the high 20's idle, mid-high 60's load on a GTX 770.
I got the window version (it was cheaper). I usually keep it on low/medium with the built in fan controller. I use high when I game, or run intensive applications (video encoding, or editing, etc.). @hans, you can't do a side fan on the window version unfortunately - this is the one thing I miss from my old case, but not a show stopper since GPU temps are relatively cool.