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