I can't speak for the other manufacturer's drive systems but the one on my own fatbike, the Yamaha PW mid drive. As of this mornings ride, I have 3324 miles on the odometer since putting the Full FatSix in service back in March, 2017.
Issues? None as of this writing. It's taken me on 20 mile runs averaging close to 17 mph using the HIGH setting to 70 mile plus day trips in the local area using the Eco and Eco+ setting to conserve battery strength. It's taken me on the local roadways as well as in the NJ Pine Barrens notorious sugar sand roads. It's been in one particular rain storm that dumped 4 inches plus in our area.....yep, I was sure I'd see the LED computer blink out and the motor to stop providing power to get me back home with some short caused by water egress. But no, it ran without one glitch at all.
I like the 70-90 RPM cadence the motor and gearing is happy in, versus the Bosch being happier in a higher cadence range. And the Yamaha PW delivers instant power when starting out, unlike the Bosch. This is not a knock at Bosch for their drive systems are a well known motor, highly regarded.
The battery on my bike is the 400 watt hour model. A 500 w/h battery is now available and can be retrofitted to the FatSix with just a simple click and go. As it stands, it is expected the Yamaha battery can deliver over 700 full charge cycles versus 500 for the Bosch. I like that kind of economy!
The 2 front chain rings is a nice touch for a bike that can tackle flat roadways and then shift down for any steep hill one has in mind to try.
In the next day or so, Yamaha is set to announce their very own line up of E mountain bikes. I wonder what they have up their sleeve that can top the Haibike as it seems there is nothing much new under the sun called mountain bike technology.....
Folk talk about a lack of a shift sensor on the Yamaha drive compared to Bosch and others. I can tell you in over 3300 miles, I act as the bikes' shift sensor by backing off the pedal pressure on a shift; no big deal at all, if you ask me. I love this bike. As much as I thought my Specialized Fatboy opened my eyes to a fat tired bike able to go anywhere, the Haibike Full FatSix takes it to a whole nother level. I couldn't be happier with the Yamaha PW mid drive and I expect Yamaha to continue to improve the motor as time goes on....
Mike