Sorry, but I would dissagree with Jac006 on this one. Sparkle just use the Nvidia reference design most of the time and yes, Gigabyte is a major manufacturer but still, even big manufacturers use the reference designs from time to time. Check the clock speeds of the two cards. I'll do a search and see if I can find them. If there is no clock speed difference then the performance difference would be within 2% of each other. The cooler is there to do it's job and gigabyte aren't known to be silent. best you could do is lookup individual reviews, at the end of the day, they are essentially the same thing using the same nVidia drivers.
well, because there is a clock difference, you have to ask yourself if the extra 40MHz is worth the extra 50quid. If you have the spare cash, go Gigabyte, other wise i'd go sparkle. They both have reputations.
you will not see a difference with two same 7800gtx but difference makers. i bet u wont even see a difference between a 7800gtx and a 6800gt. (on counter strike)
Must just be UK/European market or summint. I use them a lot in cheap builds, there more or less just products based on the manufactures reference designs so they do the job. Never had a problem with them.