For the first, I agree with Vas, it is your best. It could always use some little details besides the main fractals and C4D's used. I recommend trying to mess around with space stocks in the future. The next is eh, but not really distracting so I don't mind it there.
The effects are really cool, and I like them, but next time try and have them so they don't overpower the focal completely. Maybe remove some of the effects over him. The background is a bit blank, too.
This one, well it's not my favourite from you. The lighting is messed up. See how the lighting on the face and the can direct diagonally down, it suggests a light source coming from in front of the can. The background smudging looks to lack detail, and the foreground effects are kind nice, but theres also no detail. That topaz and text....D;
Nicooooole<3