This little kit zoom came to me autumn 2008 as a bundle with EOS450D. First I thought I'll start with it and upgrade a bit later to something more classier. To my great suprise and delight 18-55mm IS started to make really good work.
My primary photographing subjects are museums, churches and other low light situations (for I live in northern Scandinavia, where sufficient light is often very limited asset). So it was my strongest interest to have an objective with sensible chances to survive in low light. Ok, f/3.4 5.6 isn't too great to start with, but with fourth generation IS things turned rosier. 18 55mm IS has a panning feature, but better still, it really compensates objective's slow aperture. Yes, surely you can't stop the motion with these values in low light, but it is not the case for instance inside a museum.
Image quality has really stunned me. Just two weeks ago I shoot at the Parola Tank museum some indoors pics with excellent border to border sharpness. After some of the pics were made 20 x 30 cm papers, it was easy to testify what I already had figured out from the computer screen: tack sharp results!
Don't forget the weight of the 18 55mm IS, just about 200g. I also tested 600g heavy 24 105 f/4 L, which, although very impressive lens, made EOS450D (with a battery grip installed) somehow unbalanced. I see that low weight means longer shakeless shooting sessions.
To make the lens even better, Canon should upgrade it with a decent manual focusing ring and a metal mount. No USM present hasn't been any issue at all, but sometimes I really miss FTM (specially inside museums). Plastic build is nothing serious to complain about, since tolerances are quite tight and zooming operation is pleasantly smooth. After all I'm really pleased to have this tiny little wonder and am not planning to change lens.