Anyone with experience of 15-85 (and ideally 17-55mm, too)?

Dave Sparks wrote:

I have the 15-85 and the 18-135 STM - got it in a kit with the 70D, thinking that the extra range would be nice. But I prefer the image quality of the 15-85 over the 18-135 - it subjectively just looks better to me so the 18-135 sees virtually no use. I'm just keeping it as a backup and with hindsight I would have bought the 70D as body-only.I

When buying anything, I always define exactly what I want out of the device or service I am considering, and then work back from there. A major issue is what is your output format going to be? There is a huge difference between producing output for electronic media and that for producing high quality large format prints, and in between those lie a wide range of output options.

I like both the 18-135 and 15-85mm lenses for their purposes, but as I said in my previous post the question is at what end of the range do you want the extra capability. If you want an improvement at both ends over the 18-55 then IMHO the 15-85 is the way to go. If, as I interpreted it, you want to have more reach at the telephoto end without swapping to your 55-250, then I would recommend the 18-135mm unit for that purpose or go for the excellent Sigma 24-105mm F4 DG OS HSM Art lens that has outperformed Canon's own L series 24-105 (MkI) unit in tests.

With a respectful nod to Dave's comments, which are absolutely validly based on his experience, my experience was that I did not have the same issues with my 18-135mm lenses, although I took good care to test them rigorously before purchasing.  I use a wide range of gear, from modest consumer level cameras to FF professional bodies and lenses.  The one thing I would recommend is once you decide on what you want the les to do, buy the best quality glass you can afford.  Bodies change with monotonous regularity but lenses last for a long time and I have excellent results with a good lens on a modest body.

Whichever way you go, good luck with your choice and let us know how it works out!