I think that if you're happy with win, stick to it. I get paid to be a sysadmin. I work for a MS shop. I know Win like the back of my hand. If you want to learn something different go for linux. Don't be fooled in thinking the two have nothing in common. It quite the opposite, both have many similarities in the function. It's just how it is done that is different. Kick it around a little and see what you like. Whatever you do go into it with an open mind.