I should also add that I got my MG-1 in a rather poor condition with bend filter thread but ther RF was still accurate which says something about its durability. One thing I should mention is that the knob for film speed adjustment can be moved accidentally while setting the aperture ring quite easily, so you should use some sellotape there as well
I have taken one of the two favorite photos of mine with the MG-1!
I would go with the Petri 7s with a 1.8 lens. Get one if you can find one in good condition. It's fully manual and has a batteryless selenium meter so you don't have to worry about batteries