> The main downside is no GPU acceleration of anything (framebuffer only), but it's somewhat less limiting than I'd assumed, and most of my machines maintain a dual boot of Ubuntu for anything GPU intensive, though I honestly use it a lot less than I'd assumed.

You are effectively making Qubes useless. The presence of any software that has access to the EFI partition outside Qubes renders it a highly vulnerable entry point for any form of malware, as it gives direct access to Xen.