1.) 
First compact camera with two click-stopped direct control         rings, which is better than DSLRs! Few compacts have even one         control ring, and DSLRs have maybe one. 
       This means you can make your settings directly and instantly, without         the stupid press-and-spin nonsense of DSLRs. The S90 lets you 
set your         camera instantly, just like cameras of the old days. You can program         the rings as you want. I program the ring around the lens as exposure         compensation, and the one on the back as ISO. In manual mode, you can         set one for aperture and another for shutter speed — 
just like         a real camera! 
       You can flick the big front control ring with one fingertip. This is         worlds better than the dorky top-mounted thing on the 
G10 and G11. 
       2.) Fast f/2.0 zoom. This lets in twice as much light as any f/2.8 L         SLR zoom, Powershot, G series or whatever.
        3.) Full-Sized Image Sensor. Well, not really, but considering that         other makers lie about their 4/3 system DSLRs and E-P1 PEN as having         full sized sensors (they are really only have         
quarter-sized), I'm saying "full         sized sensor" here         to light up the fact that the S90 and G11 have the biggest sensors         of any compact cameras I've seen. Yes, they are a lot smaller than even         the puny 4/3 system sensors, but about 20% bigger in each dimension         (40% bigger in area) than most other compacts. (The  old 
G10 also has         the same sized sensor, but with too many pixels jammed in.) 
       OK, so it's still a compact camera sensor and won't be anywhere near as good as real SLR like a 
Digital         Rebel or       a 
Nikon D40, but as compacts go, this could be a step towards improvement.
       The most important potential improvement from Canon's "high sensitivity sensor" isn't at high ISOs, which are used infrequently, but at low ISO 80. Sadly all compact cameras have sensors so tiny that even at ISO 80 they are very noisy and use firmware noise reduction, which smudges over details. A compact at ISO 80 is about as noisy as a DSLR at ISO 800