The mafia is much more organized and much more structured. They also engage in much more sophisticated crimes as well as controlling unions and various industries.
They also assimilate MUCH better than a gang. Gangs are for kids. Anyone in his 30's thats in a gang and wearing baggy pants needs to go see a shrink as well as take an IQ test.
I saw a documentary on MS13 and although they are violent, they looked ridiculous. Can you imagine one of those idiots controlling a construction site or controlling the garbage industry?? They NEVER would be able to do it. They lack the sophistication and will never assimilate. Gangs are more of a nuisance.
Most mob guys also conduct themselves MUCH better than any of these so called gang members.