primarily less bloat, better performance and broader functional expandability. I am finalizing an installer now so that people can play around with it on their remotes without needing to build from source etc.
The user interface demo on the website is compiled in webasm from the actual GUI source, so the look, feel and responsiveness are identical to what is on the remote (obviously you can use the physical keys on the remote to navigate and interact with everything - touch is optional, not required).
I am finalizing a cross-platform installer that should be ready soon. This will allow you to backup your android settings etc, and install couch for testing. Follow the github page for updates.