MSI GTX 570 TWIN FROZR III or ASUS GTX 570 CUII??

I'm in dilemma to choose wisely which is the best for my mobo (EVGA x58 ftw 3SLI)....
Can someone tell me what are the pros and cons??
I read a lot about ASUS GTX 570 CUII (since I was thinking getting this card,its cheaper) but I heard about the problem occurs when they SLI it with another 'huge' ASUS GTX 570 (upper card insanely hotter than lower card,no good airflow since it consume a lot of space for its 'hugeness').. so, I'm thinking of getting MSI GTX 570 which has smaller card in comparison.. But still, in dilemma  

im currently using:
mobo-evga x58 ftw 3 sli
processor- intel i7-930
memory- ddr3 6gb
psu- 600w(does it enough?)


Need help from the expert,
Thanks in advance,