The companies I have dealt with provide tanks and wave a rental fee if you use a certain volume. Some will let you keep the tanks if you use their service for a period of time and maintain a certain volume usage. Is it cheaper... not really. Is it convinient? You bet. I like to use a fuel stabilizer in all my machines that is also an upper cylinder lubricant with fuel efficientcy boost, ie. cetane boost for my diesel. I also mix an anti-gel in the diesels, and having the bulk tanks makes treating your fuel very easy indeed. I also get to fuel up all my stuff at home, and mix the 2 stroke stuff while I talk to my little girls. Parking is always easy, and no fighting for pumps or waiting for the only diesel pump at the station either.
They are worth it to me, not in money savings, but for convinience.