From a gameplay perspective there is very little difference.
From an aesthetic perspective there is a great deal of difference.
Most players would say who cares about aesthetics, but we are talking about a machine that over the last 20 years has transcended simply having a metal ball rolling around on a piece of cleared wood.
It is now more a collector's piece than anything else and in this regard the MMr just does not stack up against an original, in my view.
In Australia we would call the MMr a Clayton's version based on a commercial that was made promoting a non-alcoholic beverage which on outward appearances had all the basic ingredients but was lacking the unique ingredient which would have made it indistinguishable from the original alcohol based version.