Use two-factor authentication? If not, you should, because it's more secure than if you don't use it. If you already use it, then you probably remember a time when the Android setup process was obnoxious because you not only had to put in your password twice, but also had to deal with an annoying web prompt to enter the passcode. It's a hard knock life.
Google fixed the first issue a while back when it removed the second password prompt, which made us all happy. With Lollipop, it has fixed the second issue: the PIN prompt is now part of the authentication flow. No more web popup! It's all right there, and it's beautiful.
The entire setup process in 5.0 has been revamped, making it smoother, faster, and easier. On top of this, you can also restore apps from devices backed up to your Google account, among other things. Android 5.0 is definitely the biggest revamp we've seen yet, and we're just getting started.