I finished converting my wife's bike 2 weeks ago, using this kit:
https://bmsbattery.com/ebike-kit/576-q100-36v350w-front-e-bike-whole-kit-ebike-kit.html#/213-rpm-201/381-display-lcd5Now, we ended up paying about $250USD in shipping + $40CAD in customs.
No instructions, so it took a little digging around, but it works.
We got a reasonably steep hill nearby and it'll pull me (95kgs) up that hill at a 14-15km/h unassisted and you can easily maintain 25km/h if you help it along.
The PAS is pretty good, battery more than sufficient for our purpose.
Wheel build was outright dangerous and as I needed the LBS to help installing the PAS sensor (I have no idea where my crank arm puller lives nowadays) I had them tighten and true the wheel.
Also, since I was replacing a front wheel with dyno-hub/hub brake, I also had to buy a new v-brake.
Brake only disconnects the motor and there's no regen.
Still need to shorten all the wires and probably solder most of the connections.
Company was a bit of a pain to deal with and I probably wouldn't recommend them...however, they are one of the few companies that ship batteries via air. (Not sure if GreenBikeKit does).
Be prepared of getting charged multiple times for shipping. You'd think they'd figured it out by now, although I do know that shipping batteries changes quite often and can be tricky.
Best thing is that my wife loves it. It gets her on the bike and is perfect for her commute.