Well I've got one on my DRZ and its brill. Unlike the normal scotoiler you control the oil flow by squeezing the grip pump thingy. Far better to have oil and mud on the chain rather than just mud. The oil tends to wash mud off in any case - unlike chain grease. I still thoroughly clean the chain after a run (ie gunk and jet wash) but then you just spin the back wheel whilst pumping the grip and you get a nice clean lubed chain. Much better than sticky chain grease any day. I'd say a chain oiler is essential for off roading. The only downside is that you have to use the supplied grip on the left hand handle bar and its not very grippy.