I use webmin because it's free and because with the $30 I save every month, I've been able to upgrade both of my servers to 4GB RAM
I don't do a whole lot to my servers through webmin - I do look at the logs and running processes at times, but when I moved to these servers, I hired someone to do the move and he set up all my other domains and such. I have been trying to learn how to 'see' things and 'do' things simply through ssh access.