I'll guarantee that my work will be spot on but I can't guarantee that the foundation guy, the framer, the elctrician, the plumber, or the HVAC guy. A thin coat of plaster isn't structural and if a house is going to move I don't care how skillful you are or how good a job you did your plaster is going to crack. How does your guarantee address that? If you have to have a long list of disclaimers on your guarantee it isn't really a guarantee, its a sales tool. Nothing wrong with that but among us we should call it like it is.
Carpet manufacturers around here say they have a 30 year guarantee but you have to show that you've had your carpet cleaned annually by a professional cleaner and have receipts to back it up in order for them to actually stand by it.
Back on topic. Maybe I missed it but in what hinge the videos I didn't see any explanation as to why durafinish was better other than some saying it just was...