I have been using a Zidoo X6 Pro over the past month. It doesn't come pre-installed with any add-ons but it does seem to perform very well. It does 4k, comes with Android 5.1, and can be rooted. For those wanting to install their own add-ons and don't care about pre-loaded stuff outside of a pre-optimized version of Kodi. The Zidoo X6 Pro has not disappointed me at all over the past month. It also comes in a brushed aluminum casing instead of the usual plastic look.