Okay, so the SD550 hardly breaks new ground, and - coming only six or seven months after the SD500 it replaces - I'd have been surprised if it was. In most respects this is good news; the SD500 was a little gem of a camera (and the best IXUS / ELPH yet), and the SD550 is just that little bit better. Image quality is excellent (for a camera in this class), it's fast, responsive and reliable, and it is one of the few cameras on the market today that has a true 'luxury' feel to it, such is the quality of its build and materials.
Of course it's not all good news - there are still a few image quality issues that pixel peepers will baulk at; the slight corner softness, the purple fringing and the slightly muddy low contrast detail, but the smooth, clean, bright and punchy images will delight the typical user more interested in printing their pictures than zooming into them on-screen and looking for problems. I was disappointed with the new 2.5-inch screen, which has a woefully low resolution (though it's still nice to use for those of us who like to hold the camera at arm's length), and the battery life (when using the screen) could still be better, but overall this is a camera it's hard not to like, and a camera that encourages you to take it everywhere and actually use the thing.
All-in-all, then, the SD550 is everything the SD500 was - and a little more. Maybe not enough for a Highly Recommended (it's still pretty costly and the lack of any real control is unusual at this level), but certainly enough to put near the top of the list for anyone looking for a luxury point-and-shooter.