Well, as Leica does not make a 120 camera - it is difficult to compare. It feels rock solid and more than anything it feels like a very large M2! The shutter is so quiet that Cosina incorporated a small red light below the ocular that gives a small red flash - just to let you know that you have fired it!
It is fully battery dependent though - so carry a couple of CR-2 as spare. On the other hand, I have shot some 60+ rolls with mine and the battery is till fine.
Only beef I have with it is that the knurling on the focussing ring is in 90 degree increments -i.e there is knurling for a quarter of the diameter, then a smooth surface for a quarter, then knurling again and yet another smooth surface. Took a while to get the "feel" of it, particularly for street shooting when you need fast focussing! I am going to drill a small hole and tap it for a "pin" to give me a reference for focus settings (there is enough "meat" in the barrel to do it.