I have a Torqeedo, not quite the same as the Bixby, but similiar electric motor.
Here are my thoughts in general about what the motor provides us, and maybe what your expectations should be.
I rarely use just the motor alone. I use Tom Kirkman's idea of mounting the motor in a PVC adapter that plugs into my rear rod holder (I can still put my rod into the top of the adapter, so I don't lose that capability). So I also pedal along with the motor. That roughly gives me an additional .5 to 1 mph boost with a bit reduced pedaling effort. I also use it to help tow my wife around to the other fishing spots. She LOVES it!
The only times I would use the motor alone is when I am rigging up on route. Otherwise I guess I'm too bored to just use the motor alone and my legs have been Hobie trained to be constantly in motion