I've had only one transaction with them, purchasing a McIntosh preamplifier, very smooth transaction from start to finish.
As for the trade in values, in any industry where the items depreciate a lot, and do so quickly (i.e. automobiles), the dealer needs to make a sufficient margin to survive, and if the item sold needs warranty service, they must absorb that cost as well.
One of my mother-in-law's friends bought a new Toyota Camry, drove it for a week and thought it was too large a car, brought it back to purchase a Corolla, since it was beyond the "three-day limit", she got about 75% of the purchase price as a trade in!