The impression I get is that DragonFly BSD is the most innovative BSD, especially in terms of HAMMER its filesystem. So where FreeBSD and Solaris/illumos have ZFS and people use those OSs to use a stable implementation of ZFS (e.g. Joyent), people might use DragonFly BSD for HAMMER. But is it just a research project rather than something practical? Is anyone using it or HAMMER in production? Why might people use HAMMER over ZFS or another filesystem? I'm saying all this as someone who uses Linux and is most familiar with OpenBSD when it comes to the BSDs, but that's about it, filesystems are really not on my radar when it comes to do the work that I do.
I make a point of "living" each day on a different virtual machine of my farm, and the days that it's the turn of DragonFly are the most pleasurable. While openbsd has a sweet spot in my heart, the slight divergences to posix become a bit annoying at times. On the other hand, DragonflyBSD gives you probably the cleanest streamlined unix experience.
Nothing really deep. I just want to test that our codes are portable on a large variety of distributions, so I run a few virtual machines. For linux distributions, I'm quite surprised by the bold simplicity of slackware and voidlinux.
