I believe they are NOT customized versions,like AMP! from Zotac.At least the stock coolers seem identical to me,with slight differences probably just of the shell.
The price is in descending order
There are no other brands of 570 at my local store.I may find other brands if I look at other stores but I doubt I'll find anything cheaper...
In that case, I would go for the cheapest. Many people like Gigabyte and MSI, so those should be your choices. Functionally, all the stock cards should be pretty much identical. Be sure to check out the warranties and extras that come in the box, maybe there is some extra value in the bundle. My PNY came with a free HDMI cable, which can cost quite a bit if purchased separately.