Is there any place that actually sells the Musebook for that price? I was only able to find articles about it being "available for pre-order at $299.00", and one Aliexpress seller who wants 740,69€.
Nevertheless, I got lucky and was able to order one last year. It's a nice device, but software support outside of the provided Bianbu Linux (a Chinese Ubuntu derivative) is nonexistent and the future of the SpacemiT SoCs is not exactly clear. I can run Ubuntu for the BananaPi F3 (same SoC) from an SD card with working drivers and power management but did not yet succeed in installing Ubuntu on an internal PCIe/NVME SSD I added.