It's new and still suffers from some bugs and force closes for some apps, but overall it is leaps and bounds above previous versions of Android on tablets. (blog.the-ebook-reader.com)
I've written about installing apps on Android devices before, so make sure to check that page for information for beginners and where to find the apps mentioned here. (the-ebook-reader.com)
It's available for Android phones running 5.0 Lollipop or later. (uk.blackberry.com)