Towards the end of 2023 I bought myself a portable plastic piano, and the usual accessories, including a folding piano bench. It's okay, but eventually I'll buy a proper piano bench for home, and just use this to take to gigs. It has its problems, and could do with some redesigning.
There's thick cushioned top with a vinyl cover. That makes it easy to wipe down, but does mean it's going to make you sweat in hot weather (Australia is a hot country). And it makes amusing whooshing noises as you sit down and get up. Some vent holes under the seat might have been a good idea.
It also has various creaks and rattles from the legs, so not the best choice for use in a recording studio. I found it making loud annoying noises at the worst moments while making recordings.
The height adjustment range goes from too-low to too-high, and seems to have enough steps in-between, so should suit most needs. Though I added a couple of extra positioning holes to go even lower to suit an awkward keyboard playing situation I had to contend with for a while.
The height adjustment is done by pulling in a couple of plungers at the top of the legs, and repositioning where the legs lock into some holes in rails under the bottom of the seat. They're not a firm fit, so that adds to the noise of the seat. The knobs screw in, and while they can be tightened up, they have to be slightly loose to be able to adjust (or fold-up) the seat, and this can lead to them eventually falling out (as happened to someone else with the same seat, and they lost the knob). They also stick out a bit too far, and the plungers often get wedged while you're trying to adjust the seat, because they get pushed into the side of their pipe instead of along it.
Those knobs have sharp edges, and so did something else near them. Two of us have ended up with metal splinters in our fingers after handling the seat, I had to play at a gig after getting a bit very painfully stuck in my fingertip.
It's a bit of a rat-trap to carry while folded, there's nothing to stop the legs flapping about, and it bites you if you're not careful.
The rubber feet come off too easily, so I've glued mine on.