I find it is difficult to compare. Each of them were a power house in their own era. Now it looks like it is the Ndrangheta in this era.

You must also consider the following facts, the Ndrangheta never received as much public recognition( movies,books ...etc) as did the Sicilian Mafia and the LCN. No other mafia expanded to as many countries globally as much as the Ndrangheta did and are still continuing to expand today.