Very non-****ey auth. You feed it a serial, your personal info, and it registers either directly online, or with a file from another computer (can be done via a web browser on a 2nd PC, etc). At work, I've never had issues with reauth. I reinstall my system at work fairly often, since I do computer support for a living, and I've never had Vegas whine, it reauths each time without any messing about.
As noted, you can log in to their site to get your serials, updates/redownloads, etc and also see what upgrade deals you qualify for.
Also, you get to keep old versions. So you are actually getting Sound Forge 10 and 11 with this, you can stick 10 on your laptop and 11 on your desktop (which is what I did).
It isn't quite as hands-off as Cakewalk's auth, but a close second in my opinion.
It rather amazes me, since Sony are generally rat bastards, but their creative division is good. I've used Vegas at work for academic video editing since version 6 and I've been happy with their treatment the whole time.