i ride a '99 king kahuna with an 85-115mm reba u-turn. the oem fork was a 75mm manitou that had a reputation for being a bit overstated, 70mm was closer to the truth.
in any case, at 85mm the bike handles wonderfully. at 115mm it is a sluggish, laid-back cruiser. stable and OK for downhill i suppose, but i don't like it.