[[Now Implemented!] Btsync As A Windows Service]

Agreed. Pretty amazing this isn't baked into the product. Perhaps because it is aimed at more at consumers who tend to leave windows boxes logged in 7x24.

[My Preferences: 1.3 Vs 1.4]

I concur with sudoftf's suggestions. It would be a nice (abeit not critical) feature to allow customization of the predefined key provided it does not add layers of complexity. I also found email vs copy a bit confusing, especially since many windows desktops are not properly configured to launch the desired email client. Going with Copy Link, Copy Key and View QR seems more flexible without compromising usability.