SO,
I currently use Mint/Xfce 17.3
From a personal point of view, mainly based on running the final betas of ubuntu and xubuntu in a virtualbox.
The good:
snaps - excellent, or will be when people start providing them.
The ugly (or at least irrelevant):
task bar on the bottom - I prefer it on the left as with an ultrawide screen I have more horizontal real estate to spare
ZFS - if I were running a server I'd be excited but for a desktop I'm happy with ext4
scopes gone - Saves me disabling them but I almost never use desktop search anyway
systemd - I sympathise with the purists who object but I can live with it
software centre - I think used it once to install synaptic
The bad:
Min/max/close on the left of the title bar - 20 years windows and linux desktop use have hard wired me to go to the right. For me unity is a non-starter until I can reconfigure this.
Xubuntu seemed flat and visually unattractive compared with Mint Xfce. Probably fixable with some determined customisation but I could see no significant advantages.
I'll wait for Mint 18, I think.