Garo:
I'm not sure it's fair to compare the products (and required maintenance) offered/to be offered by these two reputable tuners. To the best of my knowledge (please correct me Gerald if I'm wrong), Doug generally manufactures and installs staged, high compression SC packages that produce 200 to God only knows extra HP. Sean is about to complete and supply (not install) a production "bolt on" SC package that is less expensive and produces comparatively less HP (approx 150) than Doug's products. IMO, I think that each is designing a product for a different type buyer and user.
Bearing the previous in mind, and since the Roe SC is not yet available) we can only speculate on the amount of routine maintenance that it will require. But his (initial) system is designed to be "bolt-on" / no maintenance. Doug's customers can speak better of what maintenance is required.
My confusing .02
Woops...just noticed Gerald's post. See above