Amazing game, a completely new type of cardgame (unlike HS-SV-T:ESL, which are variations of the same base ruleset). Very generous reward for laddering. Animated (foiled, or "golden" in Hearthstone) cards are absolutely stunning.
Note that the Standalone Gwent is very different from the minigame in Witcher 3. Gwent in Witcher 3 was basically a contest of "see who plays/decoys the most spies".
This game has a lot of 'tutor'/consistency tools, so you can consistently pull off your gameplan (unless your opponent intercepts it), and is much less highrolly or prone to bricking (unlike Aria-Dogma stormhaven, 9-mana-by-T5 ramp Dragon, good old neutral Lion Haven/ prenerf Daria .etc).
So yeah, definitely go check this game out.