The more parts, the more things that can break or otherwise malfunction. I know the Eppie horns -- even the Eppelsheim-designed horns are good, according to anyone that's played them -- but think again of Leblanc: Le Rationnel, Semi-Rationnel and Leblanc System instruments: wonderful horns, but very difficult to repair. Leblanc also had bunches of other "improvements" in keywork design that, when they were in proper adjustment, worked great. Out of adjustment sometimes = unplayable, even if it was a doo-dad that did nothing more than hold a key open. This is also why I found it interesting that the few contra players here that have had the experience of playing a straight horn and "paperclip" say that the paperclip's a better horn.