ARC LS25 MkII vs. ARC Ref MkII??

I have an LS25 MkII and am thinking of upgrading to the Reference MkII... have any of you ever done the direct comparison? I recognize that there are diminishing returns, I'm just curious about what differences you may have been able to hear. People have said that the Ref MkII has better dynamics, and that the images are better... any of you listened to both? Thanks. MGX1138