My self, i have just got the Arc midi R2 case and i do like alot - But i will do some moding on it. So i can use a 360 rad in the top and a 240 in the front. But i will work fine whit Air cooling and you can put 2 x 240 in it whitout moding ..
True if you want to go beyond 240mm all in one coolers like the Corsair H100i, Swiftech H220 and the likes...
Otherwise go for it. True its a very snug fit but i fitted my 8 pin and 4 pin before installing the H100i and it was not problematic at all.