That depends on your preferences. If you play solely on gaming, hd radeon would be your best bet but if you do other stuff like photoshop, animations, video editing or other applications you do, then choose gtx 560.
This is a really strange comparison. Where on earth can you find a GTX 560 these days? I agree with CorvetteGuy. The only GTX 560 I could find was a refurbished one on newegg for $130. The MSi Twin-Frozr HD 7850 is $140, has a real warranty beyond 90 days, doesn't run nearly as hot and beats the tar out of the GTX 560.
Unless he's getting it off somewhere dirt cheap for second hand that is
hey i jst asked because my friends wants to sell it nd we getting nvidias latest card so ......... n i was nt knowin how well it is ....