i dont particurly like either of them, mramas looks like a grumpy old man with round eyes, while michos reminds me too much of one of my older tribal heads, which i was never a fan of...

but i chose mrama. his covers alot more of the artistic type bases compared to michos.
he used tribals in a figurative way, and incorporated demon colours to sort of frame the shaman, and separate it from the radioactive. Rad and shaman dont blend too well together and i think it was necesary to frame it like so

i think the main thing that did it for me though, was that mramas looked like it had a plan, more organised and thought out

Well i don't like half transparent messyness, even if it's made in a pro way. So i got to vote Mrama aswell, since it looks simpler and the design is more clever.

But Mrama, you can do a better mouth than that :P it looks like a bad cartoon.