I'm unfamiliar with how Canadian baseball works. In the states, AA or AAA ball is affiliate ball, that is, pro teams affiliated with MLB teams. How old are you?
I'm guessing both teams play at a high level. If true, then determine what your goals are for the coming year. Improvement? Or is the W the most important consideration for you?
Personal improvement is great, and what everyone is ultimately shooting for. However, the guys who get the most looks at tournament time are the guys who put W's on the board. Sorta depends on what level of development you're at and your comfort level with the different programs.
That said, a great coach can make bad players successful. A bad coach can allow great players to lose. Look at the Spankees...er...Yankees this year. Can you deny the talent? No. Does their record reflect that talent? No.
Ultimately, your choice depends on what you want to accomplish, and either choice may prove to be boon or bust. It's up to you to make the most of whatever opportunities you have regardless of where or who you play for.