It has been said you will find a difference, especially from the V1\V2 models.

More refined sound, each model is an improvement from the last.
Myself only have had V4 models so I wouldn't be able to help with what those differences are.

Mr. Alan Loft though retired for a couple years now, didn't enjoy the M60 V1 and 2 by the 3rd he began to enjoy what they had become.