My experience with Downtube (I'm thinking of turning it into a mini-series) - When my DT IX FS arrived all of the Bolts and nuts were overly tightened and the derailleur hanger was very bent - Fortunately I have the equipment and knowledge to deal with these - However, the right folding pedal did completely collapse within two hours of light use which at the wrong moment on a busy junction could have been dangerous - I did email Mr Lyansky regarding the pedal alone as setting up the bike is the buyers responsibility - Did he care? My conclusion was, no - As I was probably going to replace the pedals anyway I let it ride.
Not by any means a tragic series of events.
I can understand the OP being peeved and indeed emotive but it's the kind of feedback that I want from forums like this, to get real consumer experience not just hype and bumf.
Would I buy another Downtube? Well! a resounding maybe (despite the imploding pedal) It was a reasonable price and the frame is still fine after 5 years of enjoyable pootling.