Definitely worth switching. With the smoothness transition it offers, consumer won't be having a hard time switching FAS.
Yes, and no. For "legacy" apps (anything currently running now) the answer is "no" because they use an entirely different model. For native Windows 8 apps, the answer is YES. Windows 8 apps cannot be exited by the application (same for WP7 apps, by the way), but the OS won't shut an app down unless the OS is going down (not sure if it "freezes" the app on the way down and brings it back later though) or the RAM situation is dire (pretty unlikely given what typical native Windows 8 apps will do in terms of RAM and how much RAM a Windows 8 machine, even a tablet is likely to ship with).
- Keyboard Shortcuts: