I just installed Ubuntu 15.10, and, well... if I still cared about technology as much as I used to, I'd probably have jumped ship already. I hit a couple of road blocks with my Ubuntu install, and only plowed through them because I wanted to launch Steam, damnit, and didn't want to bother grabbing and writing a different install image.
My issues were:
- The final release of 15.10 shipped with a bug in the non-free AMD fglrx graphics drivers that breaks video output. They've since pushed a fix for this (last I saw it was in the pending updates repository), but gosh darn that is a sloppy bug to have at release. Not an issue if you don't want the vendor drivers, or have Nvidia or Intel graphics.
- I had to uncomment a line in /etc/gai.conf to prefer IPv4 lookups over IPv6 get my networking working. I get the motive for why it was configured as it was, but it didn't work for me out of the box, and I've never had to touch that before.
- The switcher applet for graphics drivers only really works for going from the opensource drivers to the proprietary drivers. It'll give you the option switch back, but it doesn't do a clean job of it. I had to fix things in the command line by purging all the old drivers, deleting some of the cruft that got left behind, and then reinstalling the opensource driver stack.
I've never used Mint, but it many of my friends use and recommend it. If you want Ubuntu, I'd go with LTS.