Mac to Mac sessions are probably going to be pretty reliable due to the same version of VNC code being used on both sides of the connection.
Of course, the devil is in the details, and not all VNC implementations are 100% compatible. This makes cross-platform remote control a simple matter since a VNC client running on a PC can easily connect to a VNC server running on a Mac, for example. VNC was originally developed for use on Unix systems but has now expanded to include a client and server version for virtually all popular computing platforms. The last two are supplied in an e-mail from MacStadium after you sign up. All you will need are a VNC client, the IP address of the server, and the password. In a just-out-of-the-box Mac mini, this feature is disabled, but since you need a way of connecting to your server to set it up, MacStadium has already enabled the screen sharing feature in the Sharing preferences panel which allows you to make a VNC connection from the get-go. VNC, Generally Speaking, Mac OS X comes preinstalled with a remote control package called VNC (for Virtual Network Computing). This article will cover four popular (and free!) remote control programs as well as the pros and cons of using each of them. Nearly all modern servers are "headless" (meaning they have no dedicated monitor, keyboard, or mouse) and are controlled over a network using remote desktop software.
The first question on your mind is probably "How do I control this thing?" So you have a MacStadium hosted server and you're all ready to do something with it.