A buddy if mine, that now owns a Baja, originally purchased the IMEX Stadium Truck for his first 1/5 scale. I would say it's similar to the quality of the rest of the chinese imports. Nothing spectacular. He had a few things break unexpectedly and repetativly, however, even that occurs on the Rampage. The difference is though we have alot of options available to us to get our stuff running without problems (Baja shocks, Ramtech susp braces and gears, aluminum pieces, etc. I haven't checked on the Imex stuff for a long time but I don't think there are many option part available for it still.
BTW, another buddy of mine had an Imex backordered order for 3 months. He canceled the order because he figured getting parts was going to be a PITA.