I don't have any experience with the Ricoch, but I do have a Canon S90.

For it's size I find it's a capable camera, the ISO is good for a point & shoot, you can change all the usual settings and it'll fit in most pockets.

However there are a few issues:

• Single focus point only when not in Auto (I get round this by setting the user assigned button to lock focus and then re-compose)
• When shooting RAW, the final shot shown in review is not the same as you will see back on your computer as the jpg processing also corrects quite a bit barrel distortion. It can be fixed in post but that's an extra step you need to complete.
• The flash pops up right where you want to hold the camera and the dial on the back of the camera is quite easy to knock, so sometimes you accidentally change the settings.

But overall I'm happy, it's a good cam for $400-500 AUD.

If you are willing to pay a little more and are happy to carry the camera in a bag as opposed to your pocked, have a look at the Olympus E-PL1, it has a larger sensor and you can switch lenses if needed. They seem to be going for $800-$1k AUD at the moment.

It's also probably worth looking at the Panasonic Lumix DMC-LX3, if you are interested in the S90.

There are also a couple of Sigma cameras that would be similar to the Ricoh, but again I've never used one of these.

I used Canon S90 for two weeks before returning it to the store to be replaced with Ricoh GR3. Shooting GR3 for about a month now. I'm using small cameras primarily for the street photography, usually from the close distance (1...5 meters), most of the time — in motion (taking pictures of passers by when both me and subject are moving towards each other), and in 90% without looking into the viewfinder or the screen. Most of the time I shoot in series, selecting what to keep later in the computer. So for me key factors were: ability to make quick shot (without lag time between I pressed the button and the image is taken), quick series of shots (click-click-click-very-short-pause-click-click-again), and not to wait too long between those series while the camera saves previous set of pictures. If your shooting style gives you enough time to focus and compose the scene, your priorities might be absolutely different.

My findings are:

• you really need a quick SD card — difference between 2x and 6x speed cards for that matter was tremendous
• you can not figure out real responsiveness from the published specs data — you need hands on experiece

S90's advantages over GR3:

• I had impression it meters light slightly quicker than GR3's (If you're walking on a dark side of the street with turned on camera hanging on your wrist pointing down to a relatively dark surface, and then suddenly point it to someone lit by the sun with bright background, GR3 won't adjust exposure quick enough, and you'll get overexposed picture. I think S90 handled these situations a bit better.)

GR3's advantages over S90:

• snap-shot mode (preset to 2.5m, but there are setting for 1, 5, and infinity I believe — I use 2.5) — you press the button full and it will take a picture at that very moment, not when your subject is already left the frame
• quick saving jpg series (within a second), and ready for another one, and then another

S90 disadvantages:

• too easy to turn the wheel on the back side without realizing you did it (screwing up your exposure or whatever you set it up to do — until you see the problem, which might be many many shots later)
• too slow to save a series of images (I want to press the shutter button again, and the camera is still busy, damn, do I need to carry two of them?) — takes at least 2 or even 3 seconds
• default color settings produce more cartoonish images (GR3's default look much more like film — I like that better, but it's really a matter of preference)

GR3 disadvantages:

• won't adjust exposure quick enough in a snapshot mode (so, if you see the scene you're interested in, point the camera that direction at least a second before pressing the button)
• if not in a snapshot mode (if it had time to focus) it will focus for the entire series based on the first image (bad when they are moving towards you — all closer images will be out of focus)
• because of the shape of the body it's harder than with very rectangular and predictable S90 to correctly point the camera without looking into the screen (I managed to do it for passers by on the left from me, but constantly missing when they are on the right, or when I'm taking a vertical shot of someone sitting on the ground — need more practice)

I also used Ricoh GX200 for several months. It has a 24-70mm slower zoom (GR3's is 28mm/f1.9). It's slightly slower compared to GR3 (but again — quick SD card is a must). There are rare occasions when I wish I had 70mm with me.

You could see images I'm taking with GR3 (and earlier with other cameras: S90, Ricoh GX200, Canon SD40, Nikon D2H, Leica M6... — see exif info next to images) on an everyday basis here.

This response may be far to late, but thoughts are nearly identical with "photographer"'s (post may 11th) above. I've owned the two cams in reverse order however. I was using the GRD3 from last November through the beginning of March when i had an incident with beach sand and I'm traveling so no one around service ricoh's easily. I, after much debate and a months' time, replaced it wiht the S90 which was available locally. I do very much love the S90, but honestly I still miss the GRD3 and if they both worked, I'd keep only it. THe zoom is semi nice on the S90 but I very very rarely use it - I work with primes mostly and treat these compacts as such, having bought them for the fast lenses they come with, but the S90 is not fast at all at it's zoomed range... so I keep it at 28mm. The Ricoh just felt better as many have also said.... and it took pictures in sequence much faster. I can strongly recommend the S90, but the GRD3 is a simple thing of beauty... I miss it.