I have two Bosch bikes and the actual operation of the motors and batteries is great. I have three major complaints though:
1) By far, the biggest issue is noise. The gear whine is just too loud.
2) The tiny chainrings wear too fast and are too expensive to replace, especially if you have a bike with boost spacing that requires "$pecial" chainrings. Haibike wants $130 each, I think Trek is the same.
3) Obviously, the weight is a little excessive at this point.
Other than that, the current system is really, really good. I've had zero hiccups electronically on either of my bikes, and I've ridden them *hard* offroad. eMTB mode is sweet, the batteries don't rattle (if they do, check your foam tape under/around the battery), and the system provides great torque. I honestly have no complaints about drag when pedaling without the motor. Let's hope the new system rides as well as the old, losing 2.4 pounds would be great, and hopefully it won't be as noisy.
I am kind of surprised that Trek has stayed with the current Bosch system in the face of the new competition, but maybe they knew the new system was coming soon.
It is Yamaha's turn to downsize and improve.