I haven't played much on Iso, but it is quickly growing on me.
Here's the thing with Goko (for me): I love about 90% of the interface. It looks good. The music is good for the first handful of games, but I shut it off now. But some of the buttons are too close together. so many times I've clicked end turn when i didn't mean to, or played cards in the wrong order. It gets really irritating. I can play several games on Goko in just a short period of time (but see below), which is good for me, lots of practice. It lets me try out a few things and learn whether or not they are good to try for games against real players (if a particular strategy fails regularly against the bots, it probably won't work if I try it against someone else).
But Goko has a lot of problems, too.
First, there's the pay to play aspect. I can play for free, but against bots, I'm stuck with basic dominion. I'm led to understand I can play the expansions if I play against someone who has them, but I haven't seen that for myself yet. The thing is, I have base set, and what this tells me is that they expect me to pay twice for each box. Once at anywhere between $25 and $60, depending on where I buy it to get the box to my house, and then again to be able to use those cards on Goko. I understand that not all players have the cards at home. Paying extra makes sense for people who don't want the cards taking up space, or who just prefer an online game to a RL game. Not that I have any suggestions for how to fix that problem...
Then, as someone else mentioned, it's really hard to keep track of what the bots do. You can see your turn, but they the bots go, the card bounce around the screen, some pretty lights flicker, and then it's your turn. Wait, what? More than once I'll totally caught off-guard by a card I didn't ever see my opponent buy. And then to try and figure out how it happened...
Now that I know how to see the log, this is alleviated a bit. And as far as the log goes, I don't have a huge problem with reading it.
But my biggest beef with Goko is it's unreliability. Sometimes I can play 5 or 6 games in a row with no problems. But then there are all of those times when, for no apparent reason, it just stalls. Completely frozen. It almost always does it during some animation. Then it clears, the game resumes, you click on a card, only to find it froze again. Over and over and over again. Then you'll finally get a game finished, and it won't launch the next game. Guess it's time to go find something else to do...