As someone who has used both extensively. I wouldn't say Docker and Jails are directly comparable; Jails are a lot more comparable to something like LXC.
Jails doesn't have any of the deployment, tools for creating images, building of images, registry for images etc. Docker also automates a lot of networking stuff away whereas with jails I usually have to use something like PF to set up port forwards; I also sometimes run into problems with the fact it shares the network stack with the host.
That being said, all the configuration is quite simple and building exactly what I need for running an application isn't too difficult. The big advantage after that being that I understand how everything is wired together and I can debug easier when something goes wrong. Doing it manually however takes up much more time.
Terribly late reply, sorry, but the deployment tools are all in ZFS. Giving each jail it's own ZFS file system let's you have templates with a bunch of steps done, or mass copy a complete jail. And with ZFS send/receive, you can share them.
Docker is a high-level container management tool, which uses container execution technologies underneath. Initially they used LXC, which is comparable to Jails, and in fact there's someone porting Docker to use FreeBSD Jails: https://github.com/kvasdopil/docker/blob/freebsd-compat/FREE...
Not familiar with freeBSD jails.