I wrote about it awhile ago and said that it had potential but I would have to wait for the official release to see how it panned out.
Well, it's been out for a few months and it's really good. It's somewhere between Hearthstone and Hero Academy, two games that I loved. I highly recommend it if you're interested in turn based strategy or new card game mechanics or even just good online competition.
Duelyst has come a long way and it's completely free to play (unless you want to spend money). Seriously, go check it out if you haven't.