Why would anyone pay a premium for Gsync now? nVidia is going to support Async. Async for all brands or Gsync and be married to a single vendor. I don't get it?
Probably because G-Sync is here now, and A-Sync is not?
There's also the assumption that A-Sync implementation will be equivalent in performance, one we have no way of knowing until A-Sync actually shows up in a functional form.