so . . . i've got the itch for a rangefinder. an m6 or m7 with the 28 f/2.8 or mamiya 7ii? anyone have any experience with the rollei trip 35? how sharp is it? how reliable is the shutter and so on . . . is the mamiya as concealable? whats the shutter on it like in terms of how slow of a shutter speed i can have hand held . . . can it even come close to the leica? I know 35mm is easier to get around with . . . but i really fancy that 6x7 negative.