The differences between the 4.7 and the 4.1 are pretty subtle. I have to compare the two side by side (or perhaps pick one up, I prefer the slightly thicker 4.7 handle) to tell one from the other. I've heard that the 4.1 was designed to be more general purpose and the 4.7 was intended primarily for a hammer grip, and I believe it.
Comparing the 2, I find the 4.7 has more conturing which makes the grip much more comfortable in hand. It does feel a bit bigger but only when comparing the 2 side by side.