As is his want, Derrick Goold has a detailed post about the top prospects and some general comments on the Cardinals system. It isn't too far off of the Future Redbirds list. The obvious exception is the presence of the 2012 draftees at the bottom and I'm probably the most vocal skeptic of new draftees which keeps these guys off the Future Redbirds top 20 (in Kelly's case).
It's hard to argue with this list too vociferously but Goold's piece is worth reading overall. My impression is that Baseball America is generally an upside oriented list with a focus on tools to the detriment of stats/current production. That's not a criticism but rather context for some of the differences.
Goold is also answering questions in the comments and will have a BA chat later this week.