X forwarding seems to work enough for my primary use case. I have some supermicro servers for work with a java applet for KVM. Because of a series of reasonable but unfortunate policies, I can't run the applet directly in the laptop's host OS. The best way is to run it in a VM. It's a lot better experience for me to run the applet over X forwarding despite some issues with window resizing that I suspect are related to hidpi, than to run a full X desktop in the VM. Host is osx, guest is freebsd with linux compat and oracle jre for linux.
It was also useful when I wanted to output some pixel graphics from Erlang to my Windows desktop from a program running on unixy devices. x server windows, x client on linux, freebsd, os x -- occasionally also ran with os x as x server and linux or freebsd as x client.
The key thing for me is the ability to export the gui for a single application on one system to a desktop environment on another --- I think this is possible with other systems, but it's not easily exposed. Performance and fidelity of the experience is usually not that important for me, as long as it's usable.
It was also useful when I wanted to output some pixel graphics from Erlang to my Windows desktop from a program running on unixy devices. x server windows, x client on linux, freebsd, os x -- occasionally also ran with os x as x server and linux or freebsd as x client.
The key thing for me is the ability to export the gui for a single application on one system to a desktop environment on another --- I think this is possible with other systems, but it's not easily exposed. Performance and fidelity of the experience is usually not that important for me, as long as it's usable.