A lot of time and effort goes into their stuff and the main two guys have many years of experience in the business. In my experience most of the people who bash them do so because of the price to quality myth. Humans usually equate higher prices with better and that's not always true. They do almost everything themselves and don't have to worry about markup from distributors and then retailers so they can keep the prices low.
Keep in mind that most audio stuff is marked up at least 100% from it's production cost so a piece of Schiit that sells for $250 is equivalent to something that would sell for $500 from a retail store and probably more if it's tarted up like Dagostino or similar.