I have both combination (Yellow + Blue) and there is a big difference in the Yellow stones - the looks, the feel when lapping. Not so sure in the way they hone yet... The older stone is much less speckled, more consistent color and I think it is softer, which I hear from Tony is better...

On the other hand, the Blue stones seem almost identical.

I am wondering what others have experienced.

Cheers
Ivo