As noted by a previous reviewer, my copy also has a focusing problem from 18-24ish mm. So for the wide end, I have to manually focus and take several shots while moving the focus ring a tad each time...just in case. Not such a big deal since I'm usually not in a hurry when taking wide angle shots. The rest of the way out to 125mm is sharp though. Focus speed isn't it's strong point and the FM's sound leaves something to be desired. Not too bad though.
Build is near EX-like. Weighs about 1lb. Very matte finish to match my black XT's finish. Zoom ring is smooth but the focus ring is too smooth (for MF). Could be just a copy issue. Of course, included petal hood (4 free!) is always a PLUS!
For about $120.00 more ($360), you could get the Sigma 17-70. For about $150.00 ($390), the Sigma 24-70 f2.8. Both lenses have great reviews/feedback regarding IQ. The 24-70 is MUCH larger/heavier, has no wide end, only 70mm, but it does have fast, constant f/2.8 (which is useless UNLESS you take a lot of indoor/night shots) The 17-70 is about the same size as the 18-125, has 1mm better wide, only 70mm long end, but has f/2.8 at 17mm (and only 17mm).
But for the price, it's hard to beat this lens! One word: versatility. 18-125mm is great! Ideal walkaround range in my opinion. It would be perfect (for the price, mind you) if it didn't have focusing issues on the wide end.