Have you ever co-GMed? Would you consider it? What are the pros and cons?
I've never had the opportunity to Co-GM a game before, nor have I ever seen it done in person, so I'm not really sure how well it would work for me. I tend to like having creative control, and going in 50/50 with another DM... would be difficult for me. That isn't to say I wouldn't love an assistant more of the time, someone to help me keep my notes organized, someone to bounce ideas off of (that wasn't a player), someone to help run large combats, etc. Sadly I have yet to find such a henchman.
The closest I've ever come to co-DMing is when I've had a steady game that runs every other week, with another game that I don't run playing the off weeks. That works pretty week, especially if you've got the same set of players, and can cover for each other if you need an extra week.
This is post #27 in the 30 Days of Gamemastering Challenge.