The differences between a 5083E and a similar 5000 M series are mostly in strength. The 3 point uses big tractor hydraulic cylinders to lift it, and the frame, trans and hydro pumps are all bigger and heavier duty. The E's use the engine as a frame, and the M's have an actual frame. However, the engines are the same displacement Hp and TQ. In fact they might be the exact same engines. The M series is heavier duty and that is why it costs more. It has more standard features, and creature comforts.
Bottom line is that the E series is a small utility tractor that is dressed up to look like a bigger tractor. The M series is bigger, Heavier, MORE expensive tractor trying to look smaller and fit in that market. The price is what scared me away from it.