I'm running several Pis, mostly 3B+, all headless, all via Ethernet, none of them ever saw a screen (if I really had no choice I'd do it, but I try to avoid it). So far, they all run Raspbian.
Now I have more and more often the issue that I want versions of software that are newer than in stretch (which isn't surprising since it's more than two years old), and I don't want to be starting building everything manually.
I tried installing ubuntu 18.04 server (there's a raspberry pi 3 AMD preinstalled image released by Canonical), which worked but it doesn't properly recognize the features of the CPU (/proc/cpuinfo looks very different from Raspbian). So this seems to be off.
Ubuntu Mate 18.04 (which there is a "beta 1" of... really? more than one year after release of Ubuntu 18.04 LTS?) seems not to be headlessly installable. Like I said, if I was convinced of it I'd attach a screen and keyboard, but I'm not, since I don't want something which is centered around a graphic environment which I'm not using (and hence uses more disk space) and has such an incredible delay till release, in a year or two I'd have the same issue I have with stretch now...
Is there any Linux flavour for Raspberry Pi that has a faster release cycle (or at least less delay)? Speaking in Debian terms, I'd happily go for sid, but I don't find repositories for it.