Cooling isnt great in the XL case, according to reviews however I have not seen any of them install the optional 140mm side fan which could blow over the cpu/gpu and assist greatful in cooling....
So its a bit of a grey area imo untill its tried and tested.
You dont really get good cooling in larger towers really, not unless there noisy....its a thin line you get between silence and cooling. R2/R3 has better cooling cos its a smaller case and the fans can reach all the parts inside the case the only issue is its cramped and hard to build in and u cant fit longer VGA cards... I had to remove a 120mm fan just too install my AX850 p/s, but I gotta admit my R2 has been my top case ive had, in terms of cooling/silence.
I will hopefully get the Fractual XL since I need more hdds supported and longer vga cards and for more ease of use but will see !