I updated my laptop, seems great, just like the last release. I did move my launcher to the bottom edge, that can be done with dconf-editor (doesn't appear to be a regular user interface for it). In general everything seems to work fine. Not too many changes, but as things were working well before I am OK with that.
For those who have been paying attention to the Ubuntu project for a while you will probably know that the distinctive Orange colour has a colour reference of #DD4814
. You know it, but you would be wrong. It is now #E95420
which is very very slightly different. This change appears to have been done by a group of Canonical folk who are using github and a secret trello board rather than launchpad, and it affects some things on the phone and some things on the desktop - but not others. So, if you update to Xenial and are wondering why the oranges seem a little mismatched and brighter in places (there actually are not that many blocks of solid colour to find) that is why.
I asked the community team about the change earlier this week, answers have not been particularly forthcoming but hopefully now that the release is done the designers will have a few minutes to tell us what they have done!https://lists.ubuntu.com/archives/ubuntu-community-team/2016-April/date.html#1202