This is an interesting thread. Of course you both make good arguments. And the all arguments could easily be expanded into business dealings in general.
You seem to be contractors. I tend to lean Quantum's direction. Expecially from an end consumer standpoint. The issues Quantum is attempting to help avoid are long term. I am paying for it and am the one who has to deal with maintenance and any issues over the next 5, 10, 20, etc years. You get to walk away from the job a few days later and hope/assume everything is good. I am looking for a sure thing - that's why I always buy her that extra drink. I don't want to rely on getting lucky if I can help it!