7300GS *vomit* out of 100
7300GT *less nasty vomit* out of 100
This is kind of hard to rate, I'm guessing 100 would be like a 8800GTX so in reality the 7600 cards would be really low if you keep the scores proportional.
If you want to find performance just look up some benchmarks.
The 7300 cards are an absolute waste of money, unless your so poor and need some sort of video to display windows. If you have any want to play games, DON'T BUY THESE CARDS! You'll be better off saving money with integrated graphics.
The 7600GS/GT are designed to be budget cards, and they still play games pretty well for their price. There is a very large difference between 7300 cards and 7600 cards.
The 7900GS isn't a bad choice, for the money.
It really depends on how much money you have to spend, if you have to go to performance it just goes up the list, 7300GS being lowest.
XFX, or brands in general, really aren't slow just because they are a certain brand. It depends on if the company overclocks or not, and by how much. XFX is a pretty good company, but EVGA (the best) and BFG are also good.