Search the archives and you'll see some discussion of the different lasts that Alden uses for the same style of shoe offered with the BB and Alden labels.
Also, one specific difference that comes up a lot is on the LHS (penny loafer). BB is unlined, Alden is lined. Not sure if that would affect the size you choose, but the fit of the shoe will be different...
Also, one specific difference that comes up a lot is on the LHS (penny loafer). BB is unlined, Alden is lined. Not sure if that would affect the size you choose, but the fit of the shoe will be different...