Canon makes several series of non-SLR digital cameras; each line of cameras begins with a letter-number designation. The Sx00 Elph series is the most compact. The A series has similar features but less compact. The Sx series is mid-tier—larger and more powerful. The G series is the top tier: it has a lot of the EOS features, but lacks interchangable lenses.
This is the G2, the second one in the line (as I write this the current model is the G11). For a fixed-lens digital, it's got a lot of advanced features: three different metering patterns, aperture priority, shutter priority, full manual, an option for a threaded lens ring to add filters or a shade; 2.5fps continuous, manual focus zoom, RAW mode and a histogram. And you get a hot shoe so you can use Canon EX flashes. And the list goes on. In fact, it's mostly my mother's S3 IS which came out 5 years later; the major difference being that the S3 has image stabilization and this doesn't.
Another nice feature is its ƒ/2 lens. That's unusually fast in the digital camera era.
I bought this for $13 at a thrift shop and it turns out to be working (so far). I've always wanted a little camera I could easily take with me for grab shots—spur of the moment things you see while you're out walking the dog, running errands, and such. My S100 Digital Elph tucks nicely in a shirt pocket but it's too noisy, and its point-n-shootness is annoying. I thought my S500 would fit the bill, but it turned out to be intermittantly wonky, which means it works great when I'm testing it at home but never when I need it.
As I write this, I've only had it for a few days and only took a few shots. The upside is that the camera works very well. It's a bit noisy even at ISO 50, but not annoyingly so. Image quality is surprisingly good. My first shot was indoors, in crappy lighting, hand-held without flash; I thought it would be awful, but it was pleasantly sharp and the auto-white-balance did well with mixed lighting. The only consistent problem I've seen is a tendancy to burn out the highlights, so I'll start playing with the compensation and see if if I can work out a compromise.
The one big drawback is that it's relatively large. It's smaller than my 40D, which is what I wanted: something light and simple; the G2's pistol vs. the 40D's assault rifle. But its bulk means it doesn't fit in my shirt pocket. It gets into my pants pocket as long as I don't sit down, but it's a tight squeeze. I don't like wearing cameras around my neck when I'm walking a lot because they tend to bounce. I was finally able to hook it onto a belt loop with a carabiner, so for the long run I'm either going to have to make a special strap for it to hang off my belt, or buy a special bag to do it. But either way, it's really about double the size I really want it to be.
The other most annoying thing is the lens cap, which presses on tight on the front. It's so tight that if you turn the camera on, the lens can't deploy properly and sooner or later I think it'll break the lens motor. The fix for this is to buy the screw-on adapter, which would allow me to attach filters or shades or other knick-knacks. But that makes it even larger and bulkier—exactly what I don't want.