The dragonflybsd community is great. When I was experimenting with it, their freenode channel was super helpful, often with Matt himself answering questions. I ran into a bug after an upgrade and he had a patch up in like an hour.

I've been deploying my stuff in linux containers recently, and I really like that flow. I really hope something like Jetpack (https://github.com/3ofcoins/jetpack) can eventually provide a solid OCI implementation on top of jails and hammer (not sure what containers demand of a filesystem, I know jetpack is currently focused on ZFS).

If you have a job to do I'd rather use FreeBSD but unfortunately lot's of support for popular software is missing.

I thought about using it for a big Hadoop cluster due to ZFS and jails but at that time there was no recent Hadoop port and some tinkering is often required to get rid of glibc specifics or dependencies on Linux only APIs (epoll and stuff like that)

https://svnweb.freebsd.org/ports/head/devel/hadoop2/files/

However I guess even with a good working port it's difficult to convince a team that only uses Linux for like their whole life. We somehow decided on btrfs at that time (around Linux 3.16) and I've was busy reading stacktraces and debugging hangups for a while... Hadoop somehow also triggered some bug in transparent hugepages...

So yes, Linux is mostly plug'n'play if you need a VM for a Wordpress but IMHO digging into Linux internals can be fare more challenging than grasping FreeBSD - I guess if I had the task again I'd definitely would go with FreeBSD.