Talk:M4
There are no differences of quality between the two. If the M4-P is to be preferred on that count, it is because it is the younger camera. But that is a very general verdict, and in reality, all depends on the state of the individual camera. The two cameras are mechanically nearly identical, and none is of course natively more in need of CLAs than the other. All that depends on the shape of your own specimen (when did it last go to a camera spa?)
The technical differences could be more decisive, depending on the weight you yourself give to them:
— The M4 has a self-timer, the M4-P has not. — The M4-P has a hot shoe, the M4 not. — The M4-P has a motor coupling, the M4 doesn't. — The M4-P has a (barely visible) 28mm frame in the finder, which the M4 is lacking. — The M4-P has markings for 75mm inside the 50mm frame; but if you do not use the 75mm length, then it is of course just irritating clutter.
Judge for yourself. Both cameras are of course mechanicaly superb, with a 'feel' that is not quite there in later cameras.
The old man from the Age of the M3