Upload & Sell: Off
...I decided to purchase both a used 28-135 is um and a new 55-250 and let my wife try them out to see which one she likes better.
As a one-lens-most-of-the-time lens, I like the 28-135 better. The short end at 28mm works better for me than 55mm. When I know I'll be shooting mostly long shots, then I'll mount the 55-250, but otherwise the 28-135 is a great "walk-around" lens doing most things better.
Another advantage of the 28-135: the Ring USM focus motor is fast and quiet, and because it sends distance information to the camera, flash exposures often seem to be more accurate.
Finally, because the 28-135 is designed for use on full-frame bodies, when used on my cropped-sensor bodies I feel like I'm getting sharper images from corner to corner, and less vignetting.
Indoors my 17-55 gets the most use, because of the wider short end and the faster aperture, but since getting the 28-135 I've been using the 17-55 less and less.