I own a Vega 64 (Liquid) and I am experiencing lots of issues with the Adrenalin drivers.
I got lot's of flickering (@DisplayPort) and FreeSync does not appear to work at all. Actually, when running the AMD FreeSync Demo, everything flickers and the Test Pattern is choppy/jumpy once FreeSync is enabled. When installing any Crimson driver, the issue is resolved instantly.
I tested this with two different displays (Samsung CF791 & Asus XG35VQ).