Main BionX problems have been the Chinese 48V battery disaster in 2011.
+ their software problems in 2012+2013 with version 4.x and 5.x.
Since version 6.0 the software is very good.
the BionX P motor is very good and imho quite reliable.
actual 48V batteries are said to be quite good and the last price is 600 Euro for a 52 cell battery with 3 years warranty, that's okay in my opinion, too. Sometime there is a failure with the 48V BMS, in my opinion the balancer system is quite shitty. (you can run hardware 6.2 batteries with software no older than 111 without the balancer)
Display has always been good, cables and charger, too.
I had never any sensor failures (just don't oil the axle!), but this can be fixed.
The BionX SL motors from 2011 have not been a good idea. That motors just weights 3.4kg and I assume it is quite expensive to make with double the windings and magnesium shell. Those motors overheat quite easy which is not what people expect from a electric motor in hilly regions. I'm one of the last fas of that motor because of its light weight for a silent 1300W direct drive system which is perfectly legal in EU.
The D motor is quite an engineering masterpiece (look at reason endless sphere discussion and the d-series in the simulation tool which Justin just recently added) and alone in the field in regards of weight to power/torque rating. It would also have been an excellent s-Pedelec mot easily reaching 45km/h (I ride one in an sPed, so I know).
But I assume they are quite expensive to make (just look at the inside construction!) and sometimes you have to deal with noise from resonances and I don't like the rim problems. BionX also does/did not sell replacement freewheels/clutches (correct word?) for this motor.
Me and my girlfriend have 4 bikes with BionX and all of them run silent, powerful, are freely configurable, have a legal throttle option and rarely have problems besides the typical thing of getting hot on steep and long hills. This problem is very significantly reduced with d-Motor and even the SL and P series could use ferrofluid or heatpipe through the axle which I'm experimenting with.
I own around 10 BionX motors (most of them I bought dirt cheap as "defective") and several BionX BMS, the CAN tools, the software and some spare parts. Aging battery cells are quite easily replaced in the BionX world. So I hope and assume that I will be able to enjoy the only motors with 48V 30A controllers that are perfectly legal within 250W EU rules for maybe 15-20 years to come.
I was also able to get approval + insurance for a 45km/h s-Pedelec with d-Motor that is as powerful as the most powerful s-Pedelec that are out there but with a 250W sticker and not even an obligation to wear a helmet on it, because it is based an old BionX s-Pedelec with it's 20km/h official max speed (20km/h when the rider does not move)
It's sad that people did not see and tell about the advantages of the system and sad that many people dis-advised against it, not even owning one, but I agree that you need knowledge to learn how to make the best out of a BionX system and how to fix it...
Overall the EU market seems to be quite dead for hub motors anyway. There are some motors from TDCM in Klever and Stromer with very small market share, some GoSwiss/Ortlinghaus in even smaller niche markets and maybe somewhere is a bike with an Alber motor? Add some discounter bikes with a cheap Chinese hub motor and 7 speed freewheel. I have never ever seen a bike with a Falco E motor. Anything else?
all I see is Bosch and some small competition from Yamaha, Shimano and Brose but all of them driving the chain.
. I felt sorry for him, so I converted it with a high-torque geared hub-motor for about £600.
