Just come back from holiday with my sister in law.
She has bought one of these:
Electric power paired with our easy-to-mount low step-through folding frame. On-road performance. Unrivalled practicality. The JET-E.
jorviktricycles.com
It is 250w front hub with 15Ah battery. 3 level electric assist with lcd screen. 3 speed nexus hub gear at the point where the two chains meet. Hydraulic discs front and back. Throttle seems to be walk assist only. It folds just in front of the bottom bracket.
Gear change is twist grip and is kind of pre select. You twist to change then pedal backwards to effect the change.
I rode it and it seems solid and well made, but it does have a few quirks.
The rear axle is a split axle so allowing a differential effect. However this means that only the right rear wheel is pedal powered causing a veer to the left under heavy pedalling. Probably not to much cause for concern as most riders would be relying on the motor for most power.
The rear disc is also on the same axle and brakes the right wheel only. This causes a swerve to the right under heavy braking. OK if you're ready for it but disconcerting none the less.
You have to move your upper body around considerably to keep upright. My sister in law shifts her weight around on the saddle leading to her being called Valetino (he of the superbike riding).
Being a step through, you can feel it flexing as it goes over undulations in the road and rear wheels cause the frame to twist.
Gearing seems quite high. Only had it up to about 8mph (I didn't feel comfortable any faster) and the cadence was too slow in first gear. I'm not sure I'd want to ride it at 15mph !
My sister in law rode it down a 4 mile section of the Kennet and Avon canal path and managed very well, especially considering that she has come to cycling only in the last few years (in her 70's) and bought the trike having fallen off her Seago into a canal.
She has adapted very well to the quirks of a trike possibly because she's never been a cyclist.
Many who tried it couldn't ride it. My daughter, a confident cyclist from childhhod, now in her 30's, couldn't ride it at all. I did all right having a pre-understanding of what to expect handling wise - but I didn't like it.