[rawfan]

I have actual machines that I was able to flawlessly upgrade from 4.10 to 17.04. Can't say that about Windows. Though I did actually know what I shouldn't mess with if I want the upgrade to go through (or fix before).

[osd]

You got extremely lucky. Not that windows is much better, but in general there are hiccups to upgrading with most linux distros as well as windows.

[regularfry]

I hit problems with the desktop environment on both 8->10 and 10->12, then gave up trying to upgrade Ubuntu in-place. Debian has been absolutely fine, though.