Though there are a couple of models in the "affordable" range there, they seem to be the cheap junk that has poor quality output. They literally look like someone's attempt to make their own inkjet printer and though I don't doubt they work and are "good enough" for a lot of things, that's all I think of when I look at them. What are we talking about? Three stepper motors, a control board, some supporting struts, belts, chains, gears, and a heated nozzle with a box of raw plastic on top. Just what is in there to cost several thousand pounds?
When the prices come down to something *sensible* for what is basically an inkjet printer but requiring less tolerance, less specialist components, a small bit of heat, and a Z-axis motor, then I can look at them. And though a lot of inkjets are subsidised by their ink costs, there's nothing stopping a big-name manufacturer doing the same for the 3D plastic source material either (stick it in a funny-sized box with a heater, market that as "ink" for the printer, done).
I'd love to have one to tinker with but they are basically tinker-toys at the moment, so anything past £300 is out of the question, and you need to get something vaguely useful out of them for that price quite easily. We're just not there yet.
Incidentally, I went to the BETT exhibition last weekend and despite there being a 3D printer on every stall last year, this year there was nothing. Not one. They can't even sell them to schools who do have the cash to invest in them.
Honestly, I expect to pay £50-100 for a "homebrew" one of these (i.e. the price range of a half-decent commercial inkjet, or some large homebrew lego project), and £300-500 for a full commercial-quality one. Until then, I don't see what market they serve.