I would rate online Dominion implementations like that:
1. Goko
Unquestionable leader within board games world: lobby of the greatest convenience, built-in dress-your-own-knight simulator, introduction of The Dance.
2. Making Fun
The dance goes on: chrystal ball, animations, extremely practical way of overpaying and spending coin tokens, laptop warms you up in the winter.
Not a lot of people know about it, but there was a hidden easter egg implemented: if you slided your opponent's stats bar 100 times during their turn you received a coin token.
3. Isotropic
Pretty crappy one: slow, childish UI, no animations whatsoever. The only good thing in this one was art: way better than original cards.
4. Shuffle iT
AN ABOMINATION. Everything is wrong about this one.
Now everyone can join my games and laugh at me when I lose, they can also replay my old games and laugh again.
I can't win vs good players now because if they misclick they ask me to undo it, like what the hell..
With that many expansions released it's goddamn impossible to see your favorite cards often. Speaking of which, no Stash!
Also, Russian version. Now who the hell gonna need that, jeez..