What I would like to know is the following:
Would G-Sync be able to get rid of the stuttering/hitching that we see today in some game engines that were poorly optimized? (Far Cry 3 for example).
If that's a definite Yes, then It would make G-Sync a bit more relevant to me (I play on a 144Hz BenQ XL2411T).
But I still stand firm that these two technologies shouldn't me named in the same sentence, they're completely different things.
What I find interesting is that repi (Johan Andersson) mentioned several times over the weekend that Mantle would bring "the robust stable performance that we have on consoles today", so if Mantle is able to close the gap significantly between Min FPS and Max FPS, then it would make something like G-Sync less relevant in Mantle enabled games.
I for one I'm excited for BOTH technologies, but given that I just spent ~300 EUR on my BenQ XL2411T 144Hz monitor, and ~$370 on a Sapphire HD 7970 GHz Vapor X edition, I don't see myself going out and spending ~$800 more for a problem that might not even exist on my current situation (Mantle enabled GPU and a 144Hz monitor).