I'd like to cook a whole pig in a pit or on a spit someday. Maybe I'll start with a goat to work my way up to it.
Pit roasting is fun. I've never done a whole pig, because I've never had a reason to cook that much meat (I'm not popular enough to pull of a party of that size). But I have cook lamb legs and pork shoulders a number of times. It's easy as hell, even more fun, and the meat turns out amazing. There's really no down side, unless you consider digging a large hole in your backyard a downside. Probably the best part is getting a two day party, as it takes a whole day to dig the hole, and then work up enough coals in the bonfire to actually cook the thing. Then the next day you get to enjoy the result! My best advice is to make sure your beer supply is well stocked, because you get pretty dehydrated tending a large fire for that long.