A Virtual Machine Host
It’s very easy to set up libvirt with QEMU/KVM on a Linux box and have it work for a while. It’s more difficult to have a system set up that’s going to be somewhat robust and maintainable over a longer period of time.
I am using a dedicated server from Hetzner. I have not personally had any serious problems with Hetzner, and price is the main reason that I’ve chosen them over other providers.