Ubisoft are launching a second beta round next week. They are also giving away beta codes at random intervals, but they are snapped up quickly so you'll have to pay close attention to their Facebook account if you're going to get hold of one.
In this round, you will be able to play Haven and Academy, as before, and also Dungeon and Sylvan. There are 4 different maps.
For full info about this beta round, see this page.
If you're playing the beta, please pay special attention to the bugs that still exist and report them to the developer team. What we need at this point is not merely players trying the game, but actively contributing to its improvement. You can also post your general impressions in our forum.