I believe without looking it up that both radrover & juiced have 7 speed kiddie grade shimano sprockets & shifters. Shimano makes premium products but these will not be them. I've found the SRAM derailleur on the bike left to be much more precise than the shimanos on I discount store MTB's I rode previously. I got a 10 cm x 1 cm cyst over my thumb joint from a shimano index shifter. I use twist shifters now, which was a conversion from the SRAM index shifter that came with the bodaboda left. I've also broken a shimano rear axle with my excessive weight of 180 lb. I've also had shimano axles come unscrewed and drop the balls out on a trip, requiring me to push the bike home 4 miles. No locknut installed on cheap shimano axles. You have to buy the locknut specially, in a weird 3/8"x 26 thread, which parts vendor niagarabike.com couldn't ship the correct part.
Also be sure if you ever ride in the rain, to buy a bike with disk brakes. Rim brakes fade badly when rims get wet, which they do running through puddles. I have mechanical Tektro 160 mm disks on the bike left. They got me safely down a 10% 1/2 mile grade in March at 4 mph, with 80 lb cargo. The main disadvantage of mechanical disks IMHO is that when the pad wears and you adjust them in, the force on the handle goes higher. The three disadvantages of hydraulic disk brakes are bleeding them if they leak or you put new pads on, and the cost. Also some brands use exotic fluid available only in $35 bottles from the manufacturer. Read under maintenance thread for details.
Both radrover & juiced IMHO are geared hub drives. I like these because you can ride them 95% of the time unpowered without any drag from the motor. The herd is buying mid-drives because you can get up a hill with a 350 w motor in granny gear. I do fine on 15% hills with 60 lb cargo with my 1000 W hub drives, both DD and geared. The geared hub will wear out the gears in 5000-10000 miles, a $350 tragedy boo hoo. If you wear out a mid drive gear or sprocket, and the manufacturer discontinues the model (like Bosch did some of theirs already, no support available) you get to buy an entire new >$3000 bicycle.
Riding under my own power 95% of the time keeps my heart with "nothing wrong with it" to quote the cardiologist after $5000 tests presurgery. I have electric power only for days when a 20 mph headwind would increase my commute time from 3.5 hours to 5.7 hours. (coming home from my summer camp is inflexibly timed when I am out of food or I have an appointment in town).