Twenty or thirty years ago, I had some cause to use a workmate. A housemate had one; it seemed to do what I used it for, though I didn't do anything challenging with it. It had a decent plywood top with some fairly dull finish on it.
Something like ten or fifteen years ago, my Dad bought me a workmate as a present. Using it more extensively, like most people one of the first things I noticed was that there isn't enough room between the front of the top and the metal cross-bar to get clamps in. I imagine this fault was present in the old version too (there's a certain amount of irritation with the struts underneath fouling things protruding down from the top, but I think that's an inevitable consequence of a folding design). But I also noticed that the top on this one was made of veneered chipboard (I thought "that's going to fall to bits if it gets damp". I'm careful, so it hasn't got damp yet, but would rather it had been a bit more expensive¹ [or not had the extra "feature" -- a board clamping facility that doesn't work terribly well] and had a proper top). Then I found that the flanged nuts that fit the back top to the rails protruded too far below the plastic runner. This made that part of the top wobbly, which is annoying, but a half-hour or so of boring the plastic got them to fit so that the tops didn't tip up too much when something was clamped between them.
Now, five or so years later, her Dad bought one for my partner. This is ostensibly the same model as mine, but this time the top is made of something that looks more like ply. Alas, on closer inspection it's some sort of premboard, and after only a year or so indoors, it has *warped* so that the top surface is convex. This makes it hard to clamp anything (anything flat, at least), an annoyance compounded by the fact that the finish is now something so glossy that things slip off it at the slightest provocation. I admit that I like shiny things, in their place, but the top of a workbench has no call to be slippery².
I won't hear it said that workmates are useless, though. I have a friend who doesn't do that much DIY, but his workmate sees use at least once a year. With the top opened up just so and those orange plastic pegs positioned in the correct holes (this is the only use I've seen for the slanted side of the peg), it makes a good stand for a firkin of beer.
[1] It would be nice if the "top of the range" model was much the same as the next one down, but built out of better materials. The market doesn't work like this. [2] There are solutions to this (and the other issues), I know. But if you buy a workbench, you expect it to work as a bench. I suppose shinyness sells.