I used to run Docker containers several years ago, but I found them far more frustrating to manage. --restart policies were fairly hairy to make sure they actually worked properly, the whole "link" system in Docker is pretty frustrating to use, docker-compose has a laundry-list of problems, and so on. With LXD I have a fairly resilient setup that just requires a few proxy devices to link services together, and boot.autostart always works.

Personally, I also find it much simpler to manage a couple of services as full-distro containers. Having to maintain your own Dockerfiles to work around bugs (and missteps) in the "official library" Docker images also added a bunch of senseless headaches. I just have a few scripts that will auto-set up a new LXD container using my configuration -- so I can throw away and recreate any one of my LXD containers.

[Note: I do actually maintain runc -- which is the runtime underneath Docker -- and I've contributed to Docker a fair bit in the past. So all of the above is a bit more than just uneducated conjecture.]