Clear cut neither one.
$329 can get a zotac gtx760 2gb.
$299 is not a good price either.
Go for gtx760 2gb instead. And fyi go for 270 instead rather than 270x. It is the same gpu, same shadders, everything the same just less a 6pin power connector.
One can easily stretch the bar to oc the 270 to be 270x.