It's a tough call because Miller is very good, Detroit is good at moving and developing its pitchers, and Comerica is huge. That and he should move through the minors quickly.
I'd go with Longoria because, as J said, hitters are easier to project and more of a sure thing.
OF (x3): CarGo, M. Bourn, D. Jennings
UTIL (x2): E. Encarnacion, C. Hart
BN: Cuddyer, C. Ross, J. Montero
SP: Price, Gallardo, T. Hudson, Lester
RP: Chapman, Jansen, Rodney, Putz, Cishek, Bailey