Who would you rather have?
Castro by all odds. He's a potential five tool talent. Aviles gets as much as he can out of what he has and is a good guy to get as your backup infielder.
4 tool.... 5-10 HRs won't qualify him for the 5th.
I would take Aviles. Better pedigree, Castro is young, not gonna take a big step forward this year. Though where you get either of them, you really cant go wrong for the price.
Starlin...if there wasnt so many good rookies that emerged last yr he was a runner for ROY, just hope the sophmore jinx doesnt come into effect here