After much comparison shopping, we bought a Vortex Razor 10 x 42. Cleaner and brighter than almost anything else we tried, and considerably brighter than what the naked eye sees. The $5k Swarovski was minimally better; saved almost $4k with Vortex.
Canon hasn't done well with the design of its IS binoculars. They simply haven't been sharp enough, and the sharpness matters much more than the IS for most users. Even compared to Canon's 18 x 50, you can see more with a top pair of 8X or 10X binoculars.
There are some excellent bird-watching reviews of binoculars, but if you're shopping for binoculars I additionally suggest trying the top models in your price range at a sporting goods store before buying. Eye relief, closest focus, and other specs matter too, and you really won't get a feel for overall performance or the build quality without handling them.