nice one, well done.
I have just been on a two month caravaning holiday and used it extensively in all sort of challenging situations, cannot say I have had any over or under exposure issues. Nothing that wouldn`t be normal, ie bright back ground or sun reflecting of water. I leave it in evaluative metering with only the center focus point. With both the 7D and 6D I tweak the exposure up or down a bit 1/2 or 1 stop as required, in the end evaluative only looks at the average of the picture.
The 17-55 is usm should still get a fair price, its a good lens.
Canon Powershot S95, Canon 6D,7D, Canon 40 2.8 STM, Tamron 24-70 2.8 VC, Canon 17-40 L, Canon 15-85, Canon 85 1.8, Sigma 30 1.4, 50mm 1.8, Canon 100 2.8L Macro, Canon 70-300L +Kenko 1.4 Pro 300DGX, Canon 430EX II and RS 4 Classic