I've been playing this as a way to pass the time while I excercise on a stationary bike. I'm enjoying it for what it is, but I'm finding a few faults with it. Of course, nothing is perfect.
The flow of gems keeps the games moving nicely and not too drug out unlike Magic and not drawing mana cards.
It's actually beneficial to go second as you get an extra card and the coin which gives you 2 gems on the first turn. I think this is too much of an advantage as if you do first, you generally end up not playing anything, get one less card, and are essentially a turn behind.
It's a little more simple than I'd like. Secrets allow a few interrupts, but there's no real tricky decks out there. You know, the fun ones that have all the weird mechanics. Most all decks are the same. Sure, there's a few combos and cards, but it's nothing too different out there. I'm sure this is something that could be addressed with time if the developers chose to, but it's like they wanted everything to be as balanced as possible even if that sacrifices fun.
A strategy I've found that others use a lot, especially in the arena, is to let their game timer run out all the way. It's annoying and I hate it. If someone plays that way, I'll just do the same in hopes that they decide to play right instead of trying to get you to concede because they're being dicks. There needs to be a way to stop this some how. If you haven't got the gist already, it's frustrating.
We need moar cards! I'm hoping there are expansions in the future.
All in all, I think it's a fun time waster. I really like the Magic online games that played almost exactly like a real magic game and was a bit disappointed by the Magic 2014 I downloaded the other week.