It's playable, very alpha still. Impressed they are this far already, though. It's really tough to tell what the hell is going on and what any ability is doing right now, but I think that would be the same with any MMO dropped in at high level.
Overall enjoyable to see, though the movement is god awful right now. It reminds me of like Starsiege Tribes 2 with 500+ ping.
EDIT: Reading the forums, apparently for the test all movement is being kept on the server to better monitor everything. That means the client sends filtered keyboard commands to the server, which then moves, then responds to the client to update position information. Knowing that it feels fine, it should clean up well once they move it to the client like every other MMO so it feels cleaner playing it.