If your speaking individual families wise then compared to other American crime groups they're small to mid-size group.
According to senior posters, Genovese is the current largest crime family with around 200 members and also the Gambinos. Gambinos had the largest membership historically and still today with only the Genovese as competition in that category. NY 5 collectively have around 700 members. Now if we compare them to other American groups than they could pale in comparison.or be equals or less. These are current or latest estimates of the other crime groups that was listed on Regan's Commission on Organized Crime:

Bandidos at 900 members.
Hells Angel at 800 members.
Outlaws at 700 members.
Pagans at 250 members.

La Eme at 350-400 members
Nuestra Familia at 250 members.
Black Guerrilla Family at 100-300 members ( Cali Only).
Aryan Brotherhood at 100 members. (Cali Only)

Obvious there's other groups like the various street gangs but there's specific picking to do. L.A crip sets like the East Coast Crips have 2,500 members and Rolling 60s at 1,600 members but the recent indictments of 52 Broadway Gangster Crips were the same size as Genovese/Gambinos. It varies from outnumber the crime families to being equal or smaller. There's crip/blood sets equal to NJ, Philly, and Outfit sized.