I had
One fitted when i bought the bike new. reason being i do a weeks ride off at a time, and the mate i tour with has used them for years and he reckons they extend the life of the chain,
As i came of 12 yrs of belt drive Muells i took his advice,
I find if you have the oil feed to high you get a very oily wheel on the chain side, as it fires it every where, Once i had the oil on the tyre, so i rapidly turned the feed down.
ride safe