Pardon resurrecting an old thread, but I just wanted to share that I had the same question!
Although BS2 sounds nice, it has far less sound possibilities than Mopho… you can have 4 seq and 4 LFOs tärouted to nearly anything you want, besides having an independent aux envelope that can be routed anywhere…
I can say i chpse the Mopho (used) and i am deeply happy with my decision! Fantastic sounding and flexible machine!