I'm all for AMD going open source with these tools (I love the fact they're doing this) but the reason that developers go with GameWorks in the first place is because Nvidia is able to allocate staff/resources to the game studios to assist in implementing.
Considering how bad GameWorks features perform in many PC games (e.g in some Ubisoft titles Nvidia-only features was dropped after release within first patches) this strategy doesn't work.
Though I only heard good things about Nvidia OpenGL developers support and as far as I know they do support even devs who isn't part of "Meant to be Played" thingy. So I suppose many studios that don't even use Nvidia-only features prefer their middleware because of support.
Sadly AMD is opposite and developers support for OpenGL just not exist. E.g you can send them emails, tickets and there won't be answer for months.
