Good company – I’ve bought several (discontinued) secondhand lenses from them in the past, and their descriptions of an item’s condition are always very accurate. Also, they usually offer me a reasonable amount when I sell them something.
But it’s worth mentioning, that it’s nearly always cheaper and more sensible to buy a *brand new and fully guaranteed* item from a reliable grey exporter, than to pay the high prices charged by MPB for secondhand goods. Just be choosy about which grey exporter/importer you use.