I've been curious about BSD in the past -- the thing that stops me is that I like to play with software that requires containers (docker) and I'm not sure if I'd ever get used to the difference between the core gnu cli utils.

The other thing that worries me is that I've had a lot of trouble building software that mainly supports BSD from source on linux machines. I'm worried if I switch to BSD, a lot of the software I want won't be available in the package manager, which would be fine, but I'm worried that building from source will also be a pain and binary releases for linux will not be compatible. Sounds like a lot of pain to me.

I'd be happy to be corrected if these are non-issues though.

You can install GNU coreutils out of the package repo no problem. Software packages are mostly available except closed source stuff that is Linux-only at which point you would use the Linux compat layer and it mostly works.

Docker is Linux-only for now but there is movement in that area. BSD had jails first and there is work on making generic containers work across multiple operating systems, including BSD. But I think the point of using BSD is to not bring Linux with you. Try their way and see how you like it.