http://www.techpowerup.com/reviews/Sapphire/HD_7950_Flex/31.html
Even at stock volts, most 7950 are capable of 1050mhz core. With ~1.2 to 1.25vcore, you think 1.1ghz is the average? Kepler at 1.3ghz is exceptional, because there's not voltage tweaking, they tend to reach 1.2ghz "average".
So in essence, its putting a max clocked 660ti vs a slightly above average 7950.. and not put in through tests where its low ROPs and 196bit bus is exposed. Fair? Informative? At least make the comments so readers will understand the strengths and weaknesses of the product.
Yes I think a 50% overclock is exceptional all things considered. I have read the 7950 OC thread here and would say 1100 is about an average OC to expect. By that I mean if you purchase a non-reference 7950 expect 1100 core to be achievable, if it goes higher then great. Just don't purchase expecting a card that will do 1250 core, that only leads to disappointment in my experience. It is the same with all graphics cards, don't expect an overclocking demon and you wont be disappointed.
In 15 years of overclocking my GPUs I can count on the fingers of one hand the number of times I got an exceptional overclocker.