No Cloud mining is profitable at all, and CEX.io is more trade site than cloud mining or hashing.  That's the only way to keep up on CEX is to continuously buy and sell hash by monitoring the price difference, which you're just better off trading at an exchange if you're going to trade.

None of the others cloud mining sites will allow you to even break even.  Not PB, not Genesis, not GAWminers, not Scrypt.cc.  Even if you're going to lose money cloud mining, at least pick a decent priced one like the following:

https://www.hashnest.com/

I hear they even give out free hash sometimes, but just don't count on making a ton of profit or ROI.