All considered, I'm happy with 16.04 and I'm staying here at
least until 18.04.
Having moved from 14.04 to 15.x, I cannot agree more.
However, many packages aren't updated in the LTS releases which prompt one to move over to the intermediate releases. I wish Canonical were more agile about updating compilers and such on LTS versions.
You can find a PPA (apt repository) for almost any app or tool these days. I find that just adding a few of these for specific cases to a LTS release gives you the best of both worlds.
My current ones: git, Google chrome, flux, node, nylas, spotify, tarsnap, blender
I went from 12.04 to 16.04. I skipped 14.04 because of the DE which I couldn't bend to my will. I remember that I had similar problems in the last months on 12.04, with some new versions of some programs unavailable on 12.04. I guess that I could have installed them in a 14.04 docker container (would the kernel version have been ok?) Maybe you can do the same for a compiler. I don't know if it would be convenient. I'm more into scripting languages and I use gcc directly only every other year or more, so no big deal for me.
However, many packages aren't updated in the LTS releases which prompt one to move over to the intermediate releases. I wish Canonical were more agile about updating compilers and such on LTS versions.