I think its much better lens than what people let you think

Rock and Rollei wrote:

I've no idea if the majority of them are decentered (although it sounds unlikely), but mine isn't. It's remarkably sharp for the money, including the corners.

I'm pretty sure a few years ago the majority of them had this defect, judging from examples in forum discussions, online reviews and the samples I tested myself. Maybe they improved production or QC after that, or maybe you just got lucky

It's considerably better than the 18-55 IS, which is actually not terrible in terms of sharpness itself.

For me the big problem of the 18-55IS is that it has a nasty kind of diffuse flare in contrasty lighting, which is impossible to remove in PP (maybe the 18-55IS STM is better, I don't have experience with that one). Sharpness is as good as the 15-85, except for the top of its range (50-55mm) where the 15-85 is clearly better. But then, my 1.8/50 runs circles around the 15-85 at 50mm, when looking at the corners ...

I was using it today on a shoot for a book. Compared to the 17-55, it's a lot cheaper, nearly as sharp, has a much wider and more useful focal length range (especially that 2mm at the wide end), has more distortion and is slower. It's a much more useful lens to me.

It has a very useful focal length range indeed, and that makes it a good choice despite my feeling that it is not very good value for money. I would prefer a 15-50mm or so instead, with higher corner quality and possibly a bit wider aperture.