Have used it for quite some time now, and have to say I LIKE IT! It is very small (especially compared to a FF 2,8 equivalents) optically speaking very useful open and real sharp stopped down even half a stop! AF is a bit slow, but okay on a 7D. (and yes, it makes 'noise'...) The tripod ring is not removable, but when not using 1D or gripped camera bodies, the ring actually is convenient to hold. (a matter of shooting styles I guess, but I actually like to put the plate of the ring in the palm of my hand making it easier to operate the zoom ring)). A tip: throw away the silly looking lens hood and replace it with the one from Canon's EF 70-200 4,0L (non IS) that fits great and gives much better shielding against bright lights. In short: a very light, fast, optically very acceptable alternative on a cropped body!