I bought that lens for when I went skiing some weeks ago just to save some space and I was absolutely not disappointed. Great sharpness, easy to use and dirt cheap. I returned it afterwards though because I got a Tamron 24-70 2.8 which magically covers the focal length of 40mm and I saw no real reason for keeping it besides the size, which I do not need that often, because I carry around my stuffed camera pack anyway.
I have both, used to use the 24 & 28 mm focal lengths on APS quite often, so when I upgraded to the 6D, the 40mm magically sits between the two
Depending on my work (mostly nightclub and party photography) I'll often have the 40mm on for weight considerations, or the 24-70 if I need versatility