Mono is obviously more reliable and cheaper.
But if you are like me and can't take it without bathroom issues of the watery kind, i would recommend a blend of others forms.
I'm using Green Magnitude from Controlled Labs and i am really satisfied (dicreatine malate and magnesium creatine chelate). Effective, packed with betaine which is also a staple and taurine + L-tyrosine, and not causing any digestion trouble.
For this package the cost per serving is absurdly low.