I put other. In the campaign I DM, only one person has multiclassed and another is going to when she goes up. In the campaign I play in, everyone but the two druids (myself and another person) and one barbarian has multiclassed.
In my group, the fighter took some rogue and there is a rogue who wants to be a druid. In the group I play in, we have a Ranger/Sorcerer, a Wizard/Fighter, a Fighter/Thief/Wizard, an NPC Orc Barbarian/Fighter (learning civilized fighting)
How is it working out? The biggest thing I've noticed is that some people in the campaign I play in have decided that the druids are too powerful. There are some house rules that contribute to that, but I think a lot of it is the fact that my character is 11th level and can now throw 6th level spells while everyone else with spell ability aside from the other druid can only muster 3rd level spells if they're lucky and most only have 1st and 2nd level spells. There does seem to be a difference between single classed and multiclassed characters there, at least in perception.