Evga will never make radeons because they get first dibs on nvidia chips and they have been very successful being nvidia only. XFX used to sell nvidia and they were considered a great AIB but they had a falling out with Nvidia and from what I can tell the Radeon users don't hold them in much regard these days.
Sapphire will not make nvidia cards. Ever
Sapphire is part of PC Partner. PC Partner also makes Zotac cards. So the same parent company (PC Partner) makes Sapphire "exclusively" for AMD and Zotac "exclusively" for NV. But at the end of the day both AMD and NV deal with the entity that owns Sapphire.
Btw, Sapphire sells about 40% of all Radeon cards.
Also, the only 2 times I've ever had fan issues were with Sapphire Dual-X coolers. I will never buy another Sapphire Dual-X again if I intend to use it in the long term.
XFX is Pine and used to be NV-exclusive but is now AMD-exclusive. Some of their 7xxx series coolers were awful but they are the only company left in the AMD camp that even offers the option of lifetime warranty on some models. Their R9 280X and 290/290X coolers are back to being competitive. So if someone tells you "XFX sucks," you know that person is overgeneralizing, because they are focused on just a couple of XFX cards in the HD7xxx line. Treat that person's opinion accordingly.