If your Windows host need Windows update, then all the Linux guests would need to be rebooted (but seems they've managed to reduce the number of reboot significantly since last year). But regarding the performance and security, most people using Linux still prefer a Linux VM host.

Wow, not really. If perf is fine who cares about the hypervisor. Regarding reboots, if they are using hyper-v they are probably on top ofServer Core which minimises patch surface and thus reboots.