Oooo I love setting and finding multis, in particular the aspect of the guided walk. If you're careful, you can set up your cache to follow a really nice walk in a really pretty area and folks will get more from that than a standard cache 'n' dash IMHO. Choice is yours, really. You may also wish to bear in mind the extra "work" involved in finding a multi will put off some cachers, so you'll get less visitors. Also you may find a tad more maintenance is required on a multi, especially if your clues refer to signposts and info boards that can get changed on a whim. Trust me on that one!
As Stu says, it's horses for courses and entirely your choice.