The Asus is the one to get ....
http://www.guru3d.com/article/evga-geforce-gtx-670-sc-review/23
EVGA SC Boost Clock is 1046 outta the box....stable at 1200 Mhz
EVGA SC gets 3DMark Score of 8691 outta the box and 9443 OC'd
Idle temp is 29C / load temp is 78C
Noise is 37 dBA Idle / 43 dBA under load
http://www.guru3d.com/article/asus-geforce-gtx-670-directcu-ii-top-review/23
Asus TOP Boost Clock is 1137 outta the box .... stable at 1280 Mhz
Asus gets 3DMark Score of 9340 outta the box and 9839 OC'd
Idle temp is 30C / load temp is 72C
Noise is 37 dBA Idle / 38 dBA under load
That makes the Asus 7% faster outta the box than the EVGA SC, 6C cooler and almost 1/4 as loud under load (every 3 dBA is a doubling of sound level). The FTW is slightly faster than the SC, leaving the Asus model w/ just a 5% performance advantage
The Asus 670 TOP is the only card ever to get a 10.0 rating from techpowerup
http://www.techpowerup.com/reviews/ASUS/GeForce_GTX_670_Direct_Cu_II/33.html
The only difference between the TOP and the non TOP versions is that in the beginning Asus was hand picking the GPUs for the TOP series. They have since discontinued that practice.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814121637
It has the best "bang for the buck" over $300
Guru3D uses the following games in their test suite: Hard Reset, COD-MW2, Far Cry 2, ANNO 1404, Metro 2033, ANNO 2070, BFBC2, BF3, Crysis 2, AvP, Lost Planet 2. Total fps (summing fps in each game @ 1920 x 1200) are tabulated below along with their cost in dollars per frame @ 1920 x 1200:
660 Ti PE gets 851 fps for $300 at a cost of $0.35 per frame
7870 gets 701 fps for $280 at a cost of $0.40 per frame
670 DCII gets 999 fps for $420 at a cost of $0.42 per frame
670 gets 917 fps for $400 at a cost of $0.44 per frame
7950 gets 746 fps for $330 at a cost of $0.44 per frame
7970 DCII gets 924 fps for $415 at a cost of $0.45 per frame
680 DCII gets 1077 fps for $520 at a cost of $0.48 per frame
7970 gets 872 fps for $420 at a cost of $0.48 per frame
7970 GHz gets 952 fps for $470 at a cost of $0.49 per frame
680 gets 989 fps for $500 at a cost of $0.51 per frame