Last week I received a notice that I can download and install Android 5.0. I did read the online articles and I loved the look of the upgrade. It was a smooth and painless process. I didn't time it as I ran it over dinner and it was ready when I finished.
So far I like the changes. There is a learning curve as some menu items are found in a different manner. The task list I like and you can swipe off an app to close or touch the [x]. the only thing I am having issues with is that it is a bit slower and Facebook crashes regularly when I look at a persons timeline.
The graphics look great and from what I use they all have the same look-and-feel so a new person has a easier time learning how to use Android apps.
If you have an older device like mine (Google Nexus 7) you may want to check online for what others have to say before upgrading. Right now I am holding off upgrading my wife's machine until I see what the patch release does.
I am holding off on device encryption as I am reading that you take a big performance hit, especially on older machines.
Battery life seems to be a lot better. Before I would be charging my device daily and I am charging every other day.
Looks like the 5.0.1 update is out. i don't know when I will get it, but, it will be loaded and I will see if it helps some of the apps run faster.