Wow. There's a lot of misinformation mixed in with truth in this thread. Brother doesn't own Babylock. Tacony does. Brother builds most of the Babylocks and yes they are a higher end, more expensive version of Brother machines. You're paying for the Babylock name after all.
There are many sewing machine factories in the world, but only 3 factories that build sergers.
There is a lot of crossover between brands any more. Brother and Janome are the two largest wholly owned companies who build most of what we see in the US(not counting SVP who own Singer/Viking/Pfaff). Many years ago Brother badged the majority of machines, now it's Janome. They both build and badge many machines for other brands.
Never think a particular dealer can't get parts for another brand. They (or their tech) choose what machines they will or won't service/work on, unless they're contracted to only service the brand they sell. Like Sears used to be with their Kenmore brand. Until a few years ago Sears repairmen were only allowed to service Kenmores.
The information I've said here comes from a few good sources, including an honest good man who was a Babylock dealer for many years.
Cari