You'll know this already but I'd say when you're coming from FreeBSD you'll be disappointed with Docker in particular, because it serves no purpose in the (usually) well-organized BSD world where the good stuff is built from source, and developed to POSIX guidelines most of the time anyway. Docker is just a workaround for the perceived mess of shared libraries in the Linux world of multiple O/S vendors (by not using shared libs in the first place which could be solved by statically linking everything), and FreeBSD's jails is IMHO superior as sandbox technology anyway.
I found the jails ecosystem as old and creaky as FreeBSD itself; the technology is good, and everything makes sense, but after using Docker on Mac and Linux for a while, I've started to prefer the lighter-weight and more user-friendly abstractions.
If there was a Jailfile equivalent for FreeBSD and a command-line tool with the same interfaces as docker, namely `docker run --rm -it ...`, I might be staying on FreeBSD.
