I have been using the 15x50 for over three years now. The Canon IS unfortunately is not a binocular which can be summed up quickly. First of all, the IS mechanism is such that unless the binocular was more or less perfectly collimated, there will be significant unsharpness and chromatic aberration either with the stabilizer off, with it on, or both. Production tolerances do not seem to be tight enough in this respect, so you'll see some people calling them soft, others calling them sharp as anything, and whatever you want in between. They all tell the truth, I believe. Also, with the stabilization engaged, the image quality varies according to how still you hold them (less movement and shake - better resolution). In addition, at least the 15-18x models are very critical for correct interpupillary distance setting and diopter adjustment. They are also not as bright as Swaro, Zeiss or Leica premiums. Having said all this, no conventional birding binocular, irrespective of price, shows you nearly as much detail hand held or even tripod mounted, and the difference is not subtle. I own a pair of superb Nikon SE 10x42's, which has mostly gathered dust since I bought the Canons. Hand held, the Canons show one-and-a-half times smaller details than the Nikon does tripod mounted, and if the Nikon is hand held also, the difference is about 1.7 fold. They also show more in low light, all the way down to near darkness, than do traditional binoculars. This is both because higher magnification in fact helps more than a large exit pupil, and because the image stabilization helps so much when your eyes are struggling to subtle differences in shades of dark grey. The big Canons are heavy, but the 12x36 and smaller are pretty standard size for bins. With the exception of the new 8x25 IS, they work very well with NiMh recharceables, and with one fully charged extra pair in my pocket I have never run out of steam during a day of birding. If Canon were to design a model specifically for birders, 10 or 12x42-50, fully waterproof and with decent, twistable eyecups, they would create some real following. The key would be to have a binocular which would be nearly the equal of other top birding models when used without the IS, and for this they would need the lower magnification/wider exit pupil a 10x42 would give.