The Rad City has 40 lbs of torque, where the Rover has 80lbs, so twice as much. You can easily start from a stop using only the throttle on the City even on a slight incline, it is nice to get you going. Having a 672wh battery, if you were going all out you would get about 1 hour, but even all out you won't use 750 watts all the time, so I would guess 90 minutes of full throttle or 30 miles? I can easily run 40 miles at 20mph and the battery isn't "dead" at that point, but when it gets down to 2 bars I charge it up.
To me the big advantage is the lack of motor noise on the city, there is none at all with the gearless hub motor, but that is also why is has half the torque of the Rovers geared hub motor. Although it is pretty darn quiet as well, the mid drive bikes seem to be the loudest.
The only disadvantage is the overall height of the City, the pedals and seat and handlebars all all higher than a "normal" bike, this is good when riding the bike, it would be very had to hit a pedal in a turn, and you are higher, but getting on and off is a bit more difficult, if I had to do it again I would have gotten a step through, not for me, but my for my wife and daughters that often borrow my bike.