DerbyBorn wrote:
Are all the different models basically the same motor / battery / drive
units with just the odd gimmick and different heads added - or is there a
step change somewhere in the range?


The missus has a more expensive than usual one that beeps and pauses
every fifteen seconds so you can move on to the next quarter, and
flashes the handle red if you push too hard against your teeth. These
seem a bit gimmicky to me, but I suppose it's someone's job to think of
these things. Having had to dismantle a few to change the batteries,
I'd suggest that the motor and gears are actually the same. We have a
few ordinary AA battery-powered ones, too, and the batteries last far
longer than a charge does, but the action seems a bit weak.