Supply house or Box store is there a product difference?

I read some 25 different DIY forums per day sometimes 3 or 4 times a day to keep up with whats happening and to try to help folks with answers if I know them or can find the answers.
One of the most frequent questions Ive seen of late is "is there really a quality difference between a name brand faucet bought at a big box store and the same item bought at a commercial plumbing supply house".
The answer to this question can be a complicated issue but when you break it down to simple economics the only way for the pricing to be different between the 2 vendors other than volume purchasing, is the product does have to be diffferent and they differ in 2 major ways. With faucets as an example its estimated that in more than 90% of the boxed faucet sets sold at the big box stores do not have all of the hardware included to propely install the faucet, primarily the washers and nuts that are used to bolt the faucet in are excluded. The other large factor is the pop-up closures for the sink in the box store units are plastic and flimsy where the product from a professional supply house are solid brass.
Ultimately the final answer is you get what you pay for. If you want inexpensive and want to make multilple trips to get what you need from the box store then buy there. If you want value and everything you need in one package use a good supply house.
The folks at National Builder Supply make sure that you have everything you need to install your faucet all in one package and have customer service staff on hand to lend advice on installation if you get it home and have problems.