Are we talking a single campaign with rotating DMs or a group that has multiple campaigns running simultaneously?
If running a single campaign, it's best for the DMs to agree to some ground rules. For example, if one DM wants magic items to be ultra-rare, but another DM gives them out like candy, this can cause a ton of friction. It can work, however, as I've seen a group pull it off, and participated as a guest DM once.
If running multiple campaigns, the only major issue is scheduling. My group has 4 DMs in it, and we usually have 2 games running on alternating weeks. Currently we have one primary game running once every two weeks, plus my game is restarting (but is a bit irregular), and one DM who's got a bunch of one-shot adventures for when someone can't run. We use a Google calendar to track who's running when. Players have access to the calendar, plus we regularly message each other, so everyone knows what's going on each week.