Although I don't have experience with the "Walmart Bike," I used my modified electric bike to commute to work and do errands. Because the system was a twist throttle, I could ride, in my work clothes, to work and not pedal. On the way home, change my clothes, and got a good workout. In heavy traffic, I almost made, 13 miles, the same time, as the cars. I put 2500+ miles on it before a magnet went in the motor. I sold the motor, batteries & controller.* I do miss it.
I had a Breezer Uptown with a Wilderness Energy Motor and Controller. The system was awesome. The torque from the brushed motor was powerful and independent from a pedal assist. I could ride 25 to 30 mph** on the flats and very fast downhills. That was with pedaling and wished I had had a higher gear. The only down side was the weight of the system especially the three 12 volt lead acid batteries. (Which alone weighed 25 pounds) The motor was 13 pounds and not recommended on bikes with front forks. With the contoller the total package was 40 pounds added to a 30+ pound bike is a bear to pedal without assist. Range when full out 20 miles 25 miles light assist.
The placement of the battery is crucial. Mine was high on the rear rack causing several problems. The height caused some control issues. The weight, on the rear wheel caused more than my fair share of flats. Recharging, unlike London, there are very few places to recharge the bike while at work. The lead acid batteries had 300 charges in them. Their cost was much lower than LI batteries. However, LI batterries had 4 to 6 times more recharges in them than LA batteries. (so the cost over time, may be less for the LA batteries.)
The new bikes are lighter due to lithium ion batteries and brushless motors. They handle better with different battery placement. Faster recharging, and pedal assist, cause them to be smoother and easier to maintain. Some come with dual, saddle bag batteries inceasing range to 75 miles. (I have not confirmed this yet) There are those, that feel electric bikes are not true bicycles but I feel the electric bike have there place. With the cost of recharging at 10 cents per charge, it sure beats the polution & $2.70, a gallon, gasoline. Besides, it is a blast to ride and expression of drivers is priceless, for the rest there is Master Card.
*Used motor and install $325
Sold it for $175 Net $150.00
Cost of throttle $40.00
100 charges x .10 = $10.00
6 tubes 4.00 = $24.00
Out of pocket total $224.00
100 gallons x $2.50 = $250.00
On positive side $26.00
**Top speed on the flat 38mph flat.