IMHO both are designed for private owners flying themselves around, but the Mustang pitches itself halfway between a private aircraft and an entry level jet. Peronally would not buy either for Public transport Ops, maybe when they have depreciated a bit, can't think of any owner operator who has managed to make new aircraft work in this marketplace, but am talking to a few parries about managing Mustangs having discounted the Eclipse as a long shot on the production / certification hurdle. Lack of TCAS in RVSM airspace may prove an issue as a costly retrofit, and the toilet issue will artificially reduce the aircraft range to the size of your bladder.
Phil