Agreed- it may not be scientific, but it's clear-cut for me. Every chain driven distance/mileage bike I have has a scottoiler. On my old Bandit 1200, it used to eat chains in about 4000-6000 miles despite sensible lubing with spray lube/wax, and the chain needed adjusting every week or so. Usually the chain died because of tight spots.
After fitting a Scottoiler the adjustment interval was twice every 4000 miles, and chains typically lasted 15,000 miles (on my 1000 Exup I managed 20,000) and even then it hadn't stretched appreciably, and had no tight spots- the sprocket teeth had just worn to hooks, forcing replacement of both. It really did pay for itself with the first chain.
And the main benefit was not needing to scrape black tarry gunge from spray-lubes from the back half of the bike. At worst I had to wipe off a small amount of flung oil.
Little and often is the best way to lubricate. Spray lubes have to have a certain amount of gelling agent in order to stick to the chain. This attracts grit and gunge, makes a nasty grinding paste and is generally a pain to clean off.
Having said that, if you let the scottoiler reservoir run dry, or accidentally knock the feed tube off the chain, the chain dies very quickly indeed.
Shaft drive is still the best maintenance-free system though!