I say that the difference is not technical, but mystical. It is out of the mainstream and it attracts people who either followed everybody grudgingly or stayed out because they did not appreciate what Macs and PCs were in the past. To be precise, let me go back to 1940. Just read it well and you will see something in parallel with Apple. This is exactly what Apple possesses.
Leadership takes risks and bold moves.
Apple irritates the conservative and non-evolving PC makers and analyst by coming to market with something new and daring. Devastating for Apple's competitors. Apple put several of the PC clone makers on the defensive stance. The PowerBook's elegant design is bold. The G4's supercomputer performance is bold.