I bought this lens because i wanted cheap wide angle for my 10D and there were very few options on the market which came even close to 20mm with the 1.6x crop with a reasonable price. this lens felt unbelievable at first, i got ~20mm wide angle which had decent image quality! I like the zoom range, i'm happy with the image quality (for this incredibly cheap price) and the lens feels solid and not shaky.
The cons are incredibly slow af which rotates the front lens barrel, if not shot in very good light, the lens tends to miss focus completely. the AF motor is loudest i've ever heard. the front barrel rotates which makes using linear polarization filters very annoying. the M/AF switch is so tight that changing focus mode is sometimes a pain in the ass. the lens hood is tightened to the front lens barrel, and i've many times accidentally rotated the barrel when tightening the hood while the lens was on AF. it's really easy to break the AF motor if you need to play a lot with the lens hood.
ok, if you're looking for a 500-1500€ quality wide angle image, do NOT expect that this lens will deliver it! of course it won't, but for 150€ it will make you smile more than cry when in need for wide angle with 300D, 10D, D70 etc...