I have an R3 build and I have to say for the price it's great. I have the three-slot DirectCU 580 in there and it fits / runs reasonably cool, as does an NH-D14. I think you do have to be careful in terms of picking the right fan and fan type for the exhausts depending on what sort of configuration you're using, but I guess this pretty much goes for any case really.
No actual heat issues with it, I did nearly fry something the other hot day but this is clearly an issue borne out of the noise priority in the build. As long as you bear in mind the sort of thermal envelope you'll be inhabiting and plan your fans around that, it shouldn't be an issue.
I wanted as minimal as possible noise along with performance, and that has a few compromises. The R3 did however play it's part well in helping me get a very quiet build that also packs decent punch when called upon.