I prefer EVGA, MSI, and XFX (in that order - have bought products from all three companies and have been thoroughly pleased), and avoid Sparkle, Zotac, and Palit. They tend to get bad reviews and fail more frequently than the first three manufacturers.
Also, EVGA has one of the best registration/support integration systems I have experienced with any sort of product. I get response emails within an hour of asking a question, and the reps are very helpful and will work with you to get things right. When you need tech support, you can just select the registered product from a drop down box, instead of having to go through several menus selecting the model and such. It also lets them know of the warranty information of your product.
avoid sparkle.. buildign systems for people they are 3/4 for doa cards and the one that worked quit in under 6 months ... thier rma process was not bad though just annoying that it didn't last he's on the second card and its been about 4 months so time will tell if it lasts
The brands are different for different people. Some people have a different experiance with each.
Personally, i go with the most warranty, the most game bundles/accessories and the one which is looking the best.
I know its different in the UK to the US. As in the UK we get a problem with the component, we return it to the Place of Purchase, not the manufacturer. So it doesnt matter who made it as the POP has to repair/replace it.
US is different, you have more dealings with the manufacturer..
But on a personal note - i would pick anyone apart from BFG (Yes ive still seen these for sale) and Palit.
BFG - Cause they have gone bankrupt, so no more support.
Palit - Quality of the units are shite at best, 3 ive had, and 3 times the fan fins have broken. So fragile..