I tried MPB a couple of times to purchase used camera bodies. In comparison with B&H or Adorama, their customer service is what you would expect from a company selling used equipment at bottom-of-the-market prices -- suspicious, brusque, unreliable (in terms of ever getting back to me, the customer). I'm sure that they have to deal with a lot more fraud than the top tier camera stores, and if you can't afford to shop at one of the better stores, then MPB does provide an alternative. Personally, I will happily pay the 10-15% premium to get excellent the customer service, reliable delivery and knowledgeable sales staff provided by Adorama or B&H.