I see a lot of people asking for alternatives. I spent 12 months trying almost every distro I could get my hands on and have some recommendations for those interested.
This was my shortlist at the end of all my adventurism and testing.
1. Linux Mint
2. Ubuntu MATE
3. Antergos Cinnamon
Pretty short list but those are what I found I settled on as possible choices for my own use. If the goal is getting down to business and getting work done rather than fiddling with the system I think those 3 would fit most people's needs. I was a longtime Xubuntu user prior to this adventurism, and IMO there are just better alternatives though it would probably be #4 if I had one, but I'm just not a fan any longer. MATE man handles XFCE.
I leave Mint at the top because other than these security concerns, it remains the best distro for me. I love their LTS update policy, continually delivering updates to Mint during the entire support span of Ubuntu LTS. Their desktop env is also just better IMO than alternatives.
Ubuntu MATE is pretty good and for the type of person like myself who is drawn to Mint, would be a really good alternative. It's missing a few features of Cinnamon, which is superior in general for me to MATE. But overall this is what I'll install if I decided to ditch Mint.
Antergos is just Arch with a nice installer. I didn't spend a long time testing this but it would be my choice for a rolling distro. Many people I know want that and they offer Cinnamon as a main, supported environment. Might be the best of every world for some. I prefer the slower updates of LM and UM, and install newer packages through PPAs or compiling it.
As an aside, I have completely given up installing other desktop environments onto distros that didn't originally ship with them. I see people recommending that, and it may work out but it's a mess if you want to switch back in my experience. I prefer to pick a distro that ships with the DE of your choice. I would not run for example, 'sudo apt-get install cinnamon-desktop-environment', anywhere at any point. :)
Hopefully this helps someone out there looking to migrate off of Mint. I'm still using it (on 17.2 here) but may move to UbuntuMATE or Antergos Cinnamon, depending on Clem's response.