Asus brand is more reputable. Some XFX heatsink are not as good as Asus. Not to mention the final performance also different.
Even though they uses the same gpu, but end performance differ. The last time I checked, Sapphire nitro is 5 fps better than powercolor red devil. I have not check it again.
https://forums.anandtech.com/threads/computerbase-which-rx-480-partner-card-is-the-best.2493443/
You shouldn't worry too much about it. Just pick any1 AFTER you browse around what are they rough performance so you will not get dissapointed. For me, I would get the cheapest one with as best brand as I could get. If the price only differ $5, I definitely go with better brand, more, its not worth it.
Good luck