PBmining for all of life, I love it. Because cex.io have more price changes than pb mining, so I think that this is more stable than cex.io. It is not a case that I've signature of pbmining 
CEX.IO with fees and maintenance costs is very expensive but in any moment you can sell GHS - this point is very good. PBmining is probably the cheapest on market: price 0.0015 / GHS - and that is what people are looking for.
Ps. If someone decide to invest in PBmining - PM me, i will tell you how to get 5% more power for free
