Dare you compare a GF670 to that Lomography crap? In any way, quality wise, size wise, functionality wise, durability, take a pick!
It has a build in light meter, far more accurate than the one LCA 120 has.
It does not need a back.
It has a lens of far better quality (and character)
It is not a zone focus one. Have you ever tried zone focusing in 35mm? How many times have you failed focusing properly? What makes you thing that zone focusing in the shallowness of the medium format would be cool?
Have in mind that missing a frame or two in 35mm is not big deal, but in 120 missing one means a lot.
You're must be kidding, or know nothing of what else one can buy for $430 or even less.