I have to admit, the S95 just has a very nice-feeling body. It's well built, with a slightly more textured finish than the S90. The front ring can be set to control shutter speed, ISO sensitivity, exposure compensation, manual focus, white balance, stepped zoom, i-Contrast, or aspect ratio. The functions can be set independently of shooting mode, so that, for example, it can control focus in Manual mode or shutter speed while in aperture-priority mode.
One not-so-pleasant holdover from the S90: the inconvenient flash placement. Although it makes sense from a red-eye prevention perspective, most people hold their fingers right where the flash pops up.
The back controls remain basically unchanged from the S90, although the dial is better and not quite as free-spinning as the previous model. I do have the same problem as Josh, who reviewed the S90, with the review button--I keep hitting it accidentally.
The ability to save a group of custom settings for quick mode-dial access is very nice. I find the placement of the shutter button a little too far toward the middle--I feel like I have to reach--but that's just a personal preference.