If and only if big polaris is enough more impressive than big vega that losing freesync support is worth it, big polaris, in all other cases big vega barring a true successor to the < $250 290s and even then I probably need the raw power. Also I really want the AMD top end CLC so I can go full moonbogg and smell my GPU.
My purchasing decisions were made by a really nice refurb XR341CK I scored for $600. No way I'd go gsync over a comparable monitor and $150 extra for my next two upgrades. I mean sure I'm AMD biased, but I wouldn't have even a soft vendor lock screen if it weren't for that screaming deal. Bias is deciding ties, not outright ignoring the other side.