Difference between 5600 and 5700 series hubs

[PpPete]

Anyone know the difference between the current 5700 series "105" hubs and the previous 5600 series iteration?

I only ask because the Ribble website has the RRP of the older 5600 series as £109.98 reduced to £50.36, whereas the 5700 series are RRP £69.95 reduced to £47.96

I've been dithering between various sealed bearing hubs and more or less decided not to complicate my life and stick with Shimano's ancient but reliable loose ball technology.... and then something like this comes along to confuse me !

 

[RecordAceFromNew]

The right hand locknut unit e.g.? You can tell from the parts codes that they do share many components.

5600

5700