I got the Scottoiler vSystem V-Strom edition. Mounted the reservoir with some zip-ties to the battery box on the right side of the bike. There's just enough space between the frame and the fairing for adjustments and refill. I've got it set to the lowest setting, which is enough, and requires me to do about one additional fill between the 6000-km services.
With the oiler behind the fairing it's a very unobtrusive system. In fact, you'd have to look really hard at the bike to see that it's got an oiler installed anyway. My bike is used for commuting a lot, and gets parked in a lot of places that are not totally secure from prying eyes, petty vandalism and so forth. Think city center Amsterdam.