I tried it at one point, couldn't connect to any servers, got pissed off with the server browser and gave up.
I may try again though.
I remember that they had problems (servers didn't show up or only displaying as being either completely full or empty + high pings) during the last sale/free weekend. Maybe it was during that period that you bought and tried to play it (unsuccessfully)?
I ended up not buying it then due to those connection issues but I'm hoping that I might have a better experience this time around... because from the few times that I managed to successfully connect to a server and play it, it was actually quite fun.