I moved from M60v3's to M80v4's. I also have some older M80TI's.
The biggest difference I can tell between the v3 and v4 high frequency, is the v4's seem a bit smoother overall. It's not really fair comparing the mid range and lower, as the M80 does have more drivers, but in all honesty, they do not have a different "sound". The M80's just punch a bit harder.
I do prefer the higher end frequencies these newer versions have over my M80 TI's, generally. There are times when I kinda miss that older TI sound though.
I don't think it's worth the expense to move from the M60V3 to M60V4, personally. Not unless you possible wanted to get them in real wood, or a different color maybe. But to do it hoping your world will be rocked from a better sound......you'll be disappointed.
