I've been playing since August and it's a great game. It helps keep me exercising too, sometimes you just gotta go for a walk to chop some logs or something.
How do you feel about trying Virtual Machine Manager instead? I really prefer it over virtual box, personally. It uses the KVM virtualization built into the Linux kernel instead of needing a module like vbox.
If you want to stick with virtual box for some reason, I would make sure that all the drivers are installed on the windows guest, you should really always do that with a VM.
Every time I try to use Gnome boxes I walk away frustrated and confused. I thought it was just an alternative GUI that did the same thing as VirtManager. It's doing something behind the scenes that is very different and not perfermant. I use spice with VirtManager daily and I don't have issues, but I'm not using the spice webdav stuff either, just display I think.
I have to confess, I don't know enough about mime biology to refute that.