I'm currently setting up an Ubuntu JiffyBox as a replacement for an old root server (iron).
Virtualization seems to be the magic word. Execute the setup within a virtual machine. Up- or downgrade as you like, for as long as you like.
In-/decrease memory or cpu cores without re-installation of your server and almost instantly. Only pay for what you're really using. Download your image and mount it locally and play with it. Backup and Restore your whole server with one click. Automatic weekly/monthly full-backups, one manual backup anytime you like. Use a webconsole and watch your server booting. Nice.
For now it seems working well. I'll report back when the server is completely setup.