I'm glad to see this new Virtualmin control panel as an alternative to cPanel, Plesk, Ensim, etc. Wish to see it getting its feet down to the web host market..
Just some feedback for the UI. The icons, design and theme are standardize enough, but I think it lacks of navigation user friendliness.
There is a field study called Human-Computer Interaction and there are some rules of where the main menu should sit on. Example, menu should be always on the left hand side, like what Plesk did. It helps a lot for new users to figure out what it's all inside. The first impression when I view the Virtualmin, I felt a bit lost. Also the text should go smaller a bit, such as 10px, or 11px.
Just some minor changes to the UI, it will give people very good impression that will drive to the success adoption.