I've only used the site once, to buy two blades for my Cuisinart, but the transaction was flawless. They had what I needed at the best price I could find on the net, ordering was easy, and the blades arrived quickly.
The grill part I ordered was out of stock. Marbeck.com notified me and gave me the chance to cancel order or wait until item was in stock. I canceled, and soon received a confirmation of a full refund as well as an 'updated order' report showing the cancellation/refund. Prompt email responses.