My mum had an electric one too for a couple of years. It worked well in that I wasnt strong enough to take her weight getting her in or out. She wouldnt try a blow up one as she said she had no confidence it wouldn't wobble .
Same problem as DD's mum with washing , and if I was buying again , Id get one with the biggest cut out U shape at the front , that I could get. Another slight problem is that you have to have the water quite deep as the seat even when lowered on some models, is still quite a few inches from the bottom of the bath ,so you cant that easily have a real good deep soak.
Secondhand ones can be a good buy , but you may find the battery is at the end of its life, and about 5 yrs ago a replacement one was about £35+ if I recall.
If theres more than one person living in the house though, its a bit of a nuisance lifting the contraption in and out of the bath, although some units are lighter than others, which may be a consideration if thats whats going to happen
My mum used to use a soap free liquid partly for her skin, and partly because it reduced any deposits like ..., on the equipment.
As they are 'freestanding' you can take them visiting too, to use in a different bath . They fold down and will go in the boot.