I think the one drawback is the low rate of pay. 0.04 per month is pretty low compared to the competitors.
For some though, the low maintenance aspect makes it totally worth it! I make 0.023 per 4 weeks at the moment (gradually rising as I post), but have no commitments to adhere to, I also don't have to prompt them to pay me.
Fair enough, it's obv from the market that it's worth it to some folks. I think that I'd probably try to switch to bitmixer.io when I was going out of town for a while or something. But if I'm actively posting and hanging out on the forum, it's nicer to quadruple my income, you know? Of course I'm not actually eligible for bitmixer.io yet, but you know what I mean.