I have heard horrible stories about it, the quality control simply isn't there on this lens.
Well the 24-105 doesn't have quite as many reviews at this point as the 24-70 or 17-40 (72 vs 200+) but you'll notice all 3 of those lenses are all at an 8.9 rating. My 24-105 is better across the frame and from a vignetting standpoint then the Tamron 28-75 I had. And my Tamron was on par IQ wise with a 24-70 I sold last year. I think your heresy experience with the Tamron seller may be an exception and probably doesn't warrant your statement above.
