BT:

You figured it out. Split brushes are for remotes--on all the brands. The swivel is really just a loose handle near the plug end--and does not work as well as they would have you think, but it does no harm. Sorry LL is out of the remote models. It was a great price while it lasted.

The BD does a better job than the DD, and is far faster, but I have to pull my ladder out or it gets tangled. That's easy enough. Plus the bag is far easier to clean but just as fine. Also, if you have a problem, Dolphin will give you a hard time, BD is just the opposite. The DD has more float controls, but you never need them on the BD as its suction is so much greater. The DD's remote is more sophisticated than the BD's, but, for me, it's not enough to justify a DD again.

Carl