Here's Digital Camera Info's conclusion on their comparison of the Canon SX1 IS and Sony Cyber-shot HX1:

The choice between the Sony DSC-HX1 and the Canon SX1 is a tough one; both scored well in our tests and provide an excellent selection of features. The Canon had the edge in a few of our tests (color and noise in still images), but the Sony came out tops in others (such as resolution, image stabilization and most of our video tests). In the end, the choice will probably come down to the appeal of some of the extra features that are on offer (such as the Sony's excellent panorama and low light shooting features) or price: the Sony is $100 cheaper than the Canon SX1.

Panasonic Lumix DMC-ZS3 vs Canon Powershot SX1 IS: Fringing – Mike Perlman of InfoSyncWorld offered up this interesting bit of information on one aspect of image quality differences between the Canon SX1 IS and Panasonic ZS3 / TZ7:

So, RAW was really the only way to shoot with the PowerShot SX1 IS. But even then, we discovered some unwanted noise and fringing. What's really interesting is that the Panasonic Lumix DMC-ZS3 exhibited far less fringing than the PowerShot SX1 IS, and both cameras were tested side-by-side.

Canon PowerShot SX1 IS Review and Sample Photos at InfoSyncWorld – Rating Score: 73% (GOOD), and Mike Perlman writes:

The Canon PowerShot SX1 IS's viewfinder was one of the better electronic displays we've seen in this class, and the picture was not too shabby. It was difficult to utilize the Manual Focus Assist function while using the viewfinder because the small screen and compromised resolution were a deadly combination, so there were certainly instances where we preferred the LCD to the viewfinder. Playback was chock full of our favorite features like Auto Rotate and offered full image data with histograms. There's no doubt that the Canon PowerShot SX1 IS offers one of the best interfaces in its class.

Towards the end of the review, you'll find links to 11 full-resolution sample images and six still captures from HD video clips. Mike says this of the first HD example:

The first video clip was highly impressive to watch, particularly because the Canon PowerShot SX1 IS rendered the scene almost flawlessly. We couldn't believe the level of detail and naturalistic color that came out of this compact.

Digital compact cameras with 720p HD video – Nice summary piece by CNET Australia, which lists the following 720p HD-capable cameras:

1. Panasonic Lumix DMC-LX3
2. Canon PowerShot SX1 IS
3. Canon Powershot SD780 IS Digital ELPH / Canon Digital IXUS 100 IS
4. Panasonic Lumix DMC-ZS3 / DMC-TZ7
5. Olympus PEN E-P1
6. Sony Cyber-shot DSC-T900

The article has links to more comprehensive reviews for each camera.