QuoteSTM isn't much of an advantage unless you have a camera body optimized for it. Just the T4i and T5i that I'm aware of, maybe the SL1.
I checked with B&H and the literature - the SL-1 is optimized for the STM lenses as well.
My 18-135 STM arrived today and it is actually quite impressive. Have not tried it for video (where, of course, the STM matters) but am looking forward to doing that.
Will compare the 18-135 STM to the 18-55 STM (both on the SL-1) and decide which one to keep.
Good to know on the SL1. I've been thinking about getting one for my wife to replace her aging P&S.
18-135mm is a nice focal range, almost an all-in-one zoom. I prefer 15mm (24mm full frame equivalent) to 18mm on the wide end, but 18 is wide enough for most uses. Thanks for raising the question on the 18-135 STM, I am better informed now than I was this morning.