My view on Debian versus Ubuntu LTS for us today
When we started with Ubuntu in 2006, Debian was mired in problems such as slow releases and outdated software that drove people to run 'testing' instead of 'stable'. Ubuntu essentially offered 'Debian with the problems fixed'; Ubuntu LTS had regularly scheduled releases, offered a wide package selection of reasonably current software, and gave us a long support period of five years. This was very attractive to us and made Ubuntu the dominant Linux here ever since (cf). However, we don't and never really have entirely liked it. We weren't enthused from very early on, and we soon came to understand various limitations of Ubuntu such as them not really fixing bugs. Recently we've come to understand that a large portion of Ubuntu's packages are effectively abandonware, cloned once from Debian and then never updated (making bug reports to Ubuntu useless).
(It's not just packages in Ubuntu's 'universe' repo that are abandonware, although being in 'universe' basically guarantees it; our experience is that packages from 'main' don't see many bug fixes either. And 'universe' is much of what's important to us.)
All by itself this has started making Debian look more attractive to me. Debian doesn't have the reliable release schedule of Ubuntu but these days it's managing roughly every two years (which is the same as Ubuntu LTS), and we're not locked to upgrading only at a specific time of year the way some people are. Our user-facing machines are upgraded every Ubuntu LTS release, so they're already not taking advantage of the long LTS support cycle, and we would likely get better support for packages in practice. And since Debian and Ubuntu are already so close, switching probably wouldn't be too hard. But things are actually better for Debian than this, because since I looked last in 2014 Debian has gained some degree of relatively official long term support (and even extra extended LTS for Debian 7).
(Part of the extended support is driven by people paying for it, which is both good in general and means that it might be possible for us to contribute if we started to use Debian.)
As a result, I now have a much more positive view of Debian and I've come around to thinking that it'd probably be a perfectly viable alternative to Ubuntu LTS for us, and in some ways likely a superior one (although we wouldn't know for sure until we actually tried to use it over the full life cycle of a machine).
Will we actually switch? Probably not, unfortunately. Debian being just as good and maybe a bit better doesn't overcome the fact that we're already using Ubuntu and it hasn't blown up in our faces yet. Perhaps I'll do an experimental install of the next Debian when it comes out (hopefully in mid 2019) to see what it's like and how easy it would be to integrate into our environment.
(This entry was prompted by an exchange on Twitter, except that it turns out I was wrong about the Debian support duration; I found out about Debian LTS support as a result of doing research for this entry.)