Sammy added some very cool edge features...
An edge-display widgets, too, including a stopwatch and a timer. My favorite is the ruler, which you can toggle between centimeters and inches.
You can also customize the wallpaper for the edge, selecting from any photo (or a combination of photos) and a series of filters. Moving the phone back and forth will move the image slightly. This effect is actually incredibly cool.
If you're a lefty, you don't need to wait for Samsung to release a left-handed version. Just flip the phone upside-down, and the entire display will rotate 180 degrees. Of course, the home button will be on top, but you can't have everything.
When the main display is showing the home screen, the edge defaults to a go-to column of apps, which you can customize. The icons fade away when you're in an app, but you can bring them back with a swipe of your thumb, and then a single tap will switch you over. It's arguably faster and more natural than going through Android's app switcher.
As stated above.. It will be interesting to see what the screen protector folks come up with...