House brands aren't manufactured by the "house", but are built to spec by some actual manufacturer. The "house" IS the middleman. The problem is that you're likely to have a hard time learning what those specs are, and how they compare to recognized brand-name products. There is no brand reputation to judge them by. And many reviewers, whether on-line or traditional periodicals, don't include "house" brands in their comparison tests.

Personally, I count on the Amazon brand to stand for quality service and reasonable prices on items that I already know about and can comparison shop -- in other words, to be a reputable merchant. I'm not looking for them to be the brand on the goods they sell.