There are DIY kits other than Bafang, but I'm extremely happy with BBS02(s). They are preferable to my Haibike mid-drive for many reasons, a few being my wife can use throttle if desired, wiring is external so problems can be elucidated, the BBS isn't hampered by proprietary parts and is more powerful. The kits are user friendly and programmable and have either five or nine levels of assist (may be others, but that's what are on mine). If you're a DIY-type, you should enjoy the kit experience.