The Ubuntu Mate OS works very well on the Pi so is well worth a try. If you have Mate 15 already installed and want to update to the recently released Mate 16 you’ll be glad to hear that is a very simple process.
Open a terminal session
type: sudo do-release-upgrade
Answer y to the prompts.
NB: This is a lengthy process so once you’ve answered the upgrade prompts you can go and do something interesting!