Underlug is my favorite.
I love my 4" M586. It may not be as big as the 29, but I don't think I'd call it little. I usually carry it in a shoulder rig with two comp II speed loaders on the off side, but I got a couple belt slides for it too. I currently want an original nickel plated 4" or 5 7/8" M586 and a 2" M686 round butt.