I suggest the wall. I just like that look better. And don't forget to put in a light/vent fan over the shower and for Pete's sake, make sure the vent exhausts OUTSIDE! I've seen what can happen when the vent exhausts into the attic, a void or once even a dryer port.
Come summer, I may even have a few big projects to share such as shed/barn building. Help is always welcome too!
