There are some tests that show the 6850 coming out on top while other tests show the 7770. If the 6850 is cheaper, I'd say get that, but if there's not much difference or any at all in price get the 7770 as it uses less power.
the two are not horrible. if the two are bad then by your definition cards like 7750 are not good for games either. the two looks bad because they don't compete on the same level with 7770 performance wise. people with low resolution should be fine with cards like 650, 550Ti and 7750
for 1080p get hd7770 or hd6850 , for 1680*1050 or lower get hd7750 or gtx650 but keep in mind neither will let u game at max settings and aa enabled. you will have to drop details to get smooth frame rates in demanding games
Any self respecting budget gamer isn't going to get a crappy gtx 650 as it is already near its max. Plus there is plenty of other options for the same price and often less. I would go with respectable cards like the 7770 or 6850 and if you are stuck in the nvidia rut then look at second hand GTX460/560 era cards.