All three are what I consider the best distributors of nVidia cards currently. MSI has the Twin Frzr version, EVGA has the life time warranty and setup program for some of their cards, Asus has a great warranty and tends to bin their cards better, which means better overclocking.
You can't go wrong with any of them. I recommend the MSI Twin Frzr or whichever is cheapest.
I wouldn't go as fa as saying its the best 470 out there, its just a factory OC'ed card with a fancy sink. To be honest I would rather go with the new MSI Twin Frozr GTX 470.
MSI Twin Frozr GTX 470 is a good card too. it is cheaper than gigabyte's. but MSI use 2 fan instead of 3 fan so customer claim MSI's card failed on 800MHz OC. If buy graphic card today, I will pick Gigabyte 470 for sure. Gigabyte product has better quality overall
My experience with MSI has been that I've never even had to worry about the warranty! Plus, it is better over the others (maybe just a tad!) because their cooling and noise (despite the fact that there are TWO FANS running!) levels are really low! You don't go wrong with them! See this: