small. i connect with my mini to my work computer frequently. i try to avoid it because my work machine has three monitors and 5120x1200 total resolution, and compressing that all down to try to fit into a 1024x600 window is tough. the mini is just fine for RDP'ing onto servers for maintenance and other purposes where a target resolution of 1024x768 is fine.
as always with RDP, it's handy to remember that if a window is stuck 'off-screen', you can usually get it back by right clicking on it's taskbar icon, choosing move, and then pressing the down arrow to snap the window to the current mouse position.