I heard about this last weekend and groaned. I've tried and failed over a dozen deepfire parts.
The only part that's done well for me is the titatnium tooth piston but as stated above, many others have had problems with it.
I'm sure that given some time, they'll improve just like the chinese clones a few years ago but for now, I wouldn't touch one with a ten-foot pole.
Grand Poobah of T.W.A.T.