Straight from the mouth of AMD's Don Woligrosky.
Source: http://www.tomshardware.com/reviews/amd-ryzen-ama,5018-11.html
PandaNation: Why are FreeSync monitors so much cheaper than their G-Sync counterparts? I know you won't be able to say much, but how does Vega compare to the Nvidia GeForce GTX 1080 Ti and the Nvidia Titan Xp? Big fan of AMD, thinking of doing a Mini-ITX Ryzen 5 build. Keep up the good work!
DON WOLIGROSKI: FreeSync is cheaper because it's an open standard. In many cases a panel manufacturer can make a FreeSync panel by changing their monitor's firmware and having it meet the spec. For G-Sync, Nvidia charges a licensing fee. Because of this differentiation alone, I think the inevitable future is FreeSync.
Vega performance compared to the Geforce GTX 1080 Ti and the Titan Xp looks really nice.
Source: http://www.tomshardware.com/reviews/amd-ryzen-ama,5018-11.html