To answer in a more general way, Mattoro is a separate factory than Heng Long, but they also act as a trading company, as many Chinese factories do, & consume a lot of HL's production. Mattoro is a toy manufacturer who started supplying their own aftermarket upgrade accessories before moving forward last year with 1/16 tank series that HL was not developing. Essentially they are competitors in the toy market but in RC tanks, they compliment each other.

Whether or not there is any appreciable quality difference is debatable. I've been told by several who bought the Matroro Stumtiger that they paid far too much compared to what their HL tanks. The new King Tiger may be a different matter, but I'd wait to see what WSN's pending release goes for before ponying up the $$$.