Ebay versus Estore

Yes, there are marketing strategies for any product out there. Companies spend countless hours and money. For Chipmunks Clothes there seems to be a marked difference from selling on Ebay versus selling from the store front itself. This 'causes me to question, what makes customers prefer a general competitive website over a personalized specific website? Is it the credibility or the thrill of the competition? Or is it the type of products available much less quality and advertising? It's a very curious study for sure!