I personally owned some old III bodies and their rangefinders were perfectly on and have had no adjustment. However, at the camera store I worked at, we had an M6 TTL which did have a rf problem. So, if nothing else, here is at least one documented case. I am also aware of users who have sent M3's back for the purpose of checking the rf because of focus problems. (never heard the final results of Leica's analysis.) But, after using many Leica rf's, old and new, and Leica SLR's, I am using the G system only, all the Leica stuff is gone. So, which is better? Obviously for me it is the G, but everyone is a different photographer and has a different basis for their opinion. I would not buy any more Leica equipment, the G proves to have too much of an advantage to justify the cost of purchasing Leica equipment.