The asus has better cooling system and it's more quiet.
The evga has better support and warranty.
Both will do, as long it's a 660 gtx, get the cheaper one by then.
In my opinion you should save up to a 660 gtx, the 650 ti is better than a 550 ti, but it's not much of a upgrade, i rather get a 660 gtx or wait for newer generation cards that might come this year.
Wait just a few months and the 700 / 8k series is going to be released. Either get one of those or a more powerful card for way cheaper than you could get now.
The asus has better cooling system and it's more quiet.
The evga has better support and warranty.
Both will do, as long it's a 660 gtx, get the cheaper one by then.