It's good to see a new batch of mid drive BBS02 clones. These seem rather similar to the Bafang, but perhaps more refined, given hindsight. Time will tell.
My personal favorite is an older mid drive using a Headline motor. This design was originated by Cyclone and sold in the US by Sick Bike Parts. Here are the sites for Cyclone and SBP:
http://www.sickbikeparts.com/catalog/pr ... cts_id=181
There are several reasons I like this one.
1. It's cheaper than the others (currently $329+ $14 ship from SBP).
2. The Headline motor uses metal planetary gears, which will last longer - but are louder.
3. The controller is separate, which I prefer though it has pro's and con's.
This setup has more power and torque than the Bafang and its clones. It's also larger, heavier and has more cluttered wiring. It's power is below that of the GNC and Lightning Rods mid drives, but good enough for my modest needs. It's not new, it's not fancy, but it's tried and true, and worth a consideration.