Atleast a little while ago it was not. I received my btb to my wallet... but for some time now they've been on a fork, IMHO. I managed to mine almost 1BTB before I noticed this.... I've tried to cashout to cryptsy and to my wallet. I received nothing. Well, that is to be expected, when mining in a fork... Pool is almost 1500 blocks behind and diff is about 20 lower than what my wallet reports at the moment...