The 16-megapixel PowerShot SX600 HS is sort of an oddball in Canon's SX and S models.
Although Canon lists this model under its "high-end, advanced digital cameras," it's really not and has more in common with the camera maker's pocket-friendly Elph line. If perhaps you didn't consider the SX600 HS because it was listed as "advanced" you should reconsider.
On the whole, the camera is a straightforward point-and-shoot with reliably good video and photo performance. But for most people, I imagine its 18x f3.8-6.9 25-450mm lens will be the big attraction along with its built-in Wi-Fi and slim, lightweight body. At less than $250 (AU$250, £200), it's also priced well for what you're getting and I would expect it to drop below $200 come holiday shopping season.
With the SX600 HS being a step-down model from the SX700 HS (about $100 separates them), you might expect a difference in image quality between the two. Fortunately (or unfortunately depending on how you look at it) the pictures are about the same, which is to say they're very good. If you aren't pixel peeping and don't typically enlarge photos beyond 50 percent and crop them heavily, you'll probably really like what you get from the SX600 HS.
The image above is several 100 percent crops from the center of our test scene. There's noise even at its lowest ISO, though you're unlikely to see it unless you are in fact pixel peeping. Canon keeps a good balance between noise and noise reduction. Though most shots from the camera can benefit from a little post-shoot sharpening, it isn't until ISO 1600 that subjects start to look really soft at smaller sizes, and ISO 3200 is mushy and should be avoided.
What's most important about all of this is that the lens is slow, meaning that it has narrow maximum apertures. That means it takes more light, slower shutter speeds, or a higher ISO when using the zoom lens to get a correct exposure and avoid blur. Even in full sun, I found the camera regularly used ISO 200 or above when fully zoomed in, so using it indoors or in low light, handheld, is basically a recipe for blurry or grainy photos.
Video quality is really very good. The SX600 HS' photos have the same noise issues as the SX600's and, likewise, soften in low light. But for shooting outdoors in daylight, the 1080p video at 30fps is better than I expected for the camera's price. You can use the camera's zoom while recording, but the lens motor can be heard in quieter scenes.
While I wouldn't classify this as a fast camera, it's not slow either, basically performing on par with others in its class like the Samsung WB350F. From off to first shot takes 1.7 seconds with a lag between shots of 1.1 seconds. Turning on the flash drives that wait up to about 3 seconds.
Shutter lag -- the time it takes from pressing shutter release to capture without prefocusing -- is just less than 0.2 second in bright lighting and 0.4 second in dim lighting. That is with the lens at its widest postion; you can expect a slightly longer time to focus when the lens is zoomed in shooting a low-contrast subject.
Canon has two continuous shooting options on the SX600 HS. You can shoot at full resolution at up to 4fps or up to 10.5fps at a reduced 4-megapixel resolution. Regardless of which you use, focus and exposure are set with the first shot, so if your subject is moving fast, it's unlikely all of your photos will be in focus.
Also, if you're shooting in Auto, the camera's autofocus system regularly picked subjects other than what would be the logical target. The problem is, there's no way to override it. Maybe it's because I've gotten used to being able to tap to focus with a smartphone, but this became overwhelmingly frustrating when I just wanted to snap a quick photo and couldn't select my subject.