I was pretty impressed with the performance and versatility of the G12. In fact I was impressed enough to buy one (with my own money at retail, no discounts from Canon!). Image quality is excellent for a compact camera. Noise performance is impressive and the ergonomics of the camera suit me well. I like the optical viewfinder, despite it's rather cramped view. I like the dual control wheels and the fast and easy manual setting of ISO and exposure compensation via dials rather than having to scroll down menus on the LCD. The lens is good and the overall size and weight of the camera mean I can carry it pretty much anywhere. I can also use my Canon Speedlites with it and process the RAW files with Canon DPP, just like I do with my DSLR files. For the very best results from the G12 it pays to shoot in RAW, though the out-of-camera JPEGs are pretty good too - just not as good as you can get with a properly processed and optimized RAW image. The ability to add filters or other 58mm filter thread accessories (via an adapter) is also something not all compact cameras have. It's useful for adding polarizer or a closeup filter for example.
Any complaints? Yes, one large one. Canon seem to have taken to not supplying a printed manual with their compact cameras. Even the G1-X doesn't come with one. You get a thin booklet which basically tells you how to put the battery in and take some test shots in program mode, but that's it. You get the full manual on CD, where it's fine as a reference but totally useless for learning the camera and everyday shooting. How much could it cost them to actually print a manual and include it with the camera? Shame on Canon for skimping. Stop listening to the bean counters and listen to the users. Provide a printed manual. Please. Add $5 to the price if you must.
Other than that there are always things you can wish for, even though you may not need them. Some people would like 1080p HD video I'm sure. A wider zoom lens would be nice too. A viewfinder with maybe 95% coverage wouldn't hurt either. A faster continuous shooting rate might occasionally be useful. However there's really nothing the G12 desperately needs (except a printed manual!).
So if you're looking for a compact camera that has many of the capabilities of your EOS DSLR, the Canon Powershot G12 has to be high on your list. It was on mine and like I said, I bought one!
• Canon Poweshot G12 at ADORAMA