I purchased a brand new Canon EF-S 55-250mm STM lens today.
The price was $1030.
Similar to the 10-18 I bought 2 weeks ago,
this lens is light but you can feel it (10-18=240g vs 55-250=375g).
It is sharp and I see no difference in color with my L glass.
Focus is fast like USM lenses, but no way as fast as my 328 (it is stupid to compare them anyway).
USM makes a "SHHHH-SHHHH" sound, but STM is completely quiet.
It makes more barrel distortion than 70-200, but you have to be shooting brick walls to tell.
There are a few funny things I discovered during the purchase:
1. I prefer the white box design than the grey box with a picture of the lens.
2. The lens box has a tear mark, but the lens is too cheap to make me care about it.
To protect the lens, I purchased a Nikon CL-1020 lens pouch.
The original Canon LP-1019 is $208, while the Nikon one is $120.
They work the same and the Nikon one is more spacious especially if you have the hood installed.
I recommend the lens, especially if you want to travel light.