Oh the Palit Sonic Edition is AMAZING!!!!
I wanted to get one before but I could not get it in my country.
If you can afford to go for the Palit card, go for it!
Btw, just to be sure, what are the other specs of your rig?
CPU, RAM, and PSU?
EDIT: Zotac is fine too but I highly recommend the PALIT Sonic Edition, has a VERY nice factory OC on it.