hey christopher... i switched from MB to MB32C a few years ago (when they were both still at v3). i haven't touched MB since then, after i migrated sessions that were still in progress. note that sessions can migrate up to 32C, but you can't take them back once you've done that. however, the migration process does automatically save a "fork" of the session, still in the old format so you can open THAT version in MB if you need to.
the sound and workflow of 32C are both much better for me, so i've had no reason to look back.