simply put, what brand do you like best in a GPU and why, this is AMD specific.
some things to take into account
features (things like different coolers and heat blocks and such, not factory OC necessarily)
customer support(RMA, not telling you how to use the product)
personally, i like asus, xfx and gigabyte, mostly because i have never had a problem with anything i ever had
although the crosshair formula IV has the problem where if you put the heat sink on all the way(its not loose or anything) it simply does not boot and does weird stuff. i have no idea if the same is with the crosshair V, but i think my next build will be the 1100t 6870 and the crosshair V because i have been happy with what i have now.