I test fitted a couple of cheap ones that a mate got through work and fitment was really poor on both. One was really badly twisted where it meets the sill and the other had a bracket in completely the wrong place. I can upload some pictures over the weekend if you like?
After speaking to a couple of bodyshops I then ordered a Euro Car Parts 'platinum' one at a trade price of £40+VAT and it fits almost perfectly, the gap between the door is 2mm wider than the OEM one, but I think that a bit of persuasion would probably sort it.
In terms of removing them, it's pretty straight forward. Grill and bumper off, wheel off, arch liner out and then 3 bolts and a nut along the top edge, 2 at the front, 2 into the sill, 2 inside the wheel arch and one in the door shut.