For me, it would be a little difficult to choose between La Rocca and Scalish. I wouldn't choose Marcello because, as Millspgh said, he had many problems with the feds, and spent a big part of the 1980s in jail, while Zammuto and Lanza were less powerful than the other 3. That leaves La Rocca and Scalish, and if I have to choose just 1, I think I would pick La Rocca just because he lived longer.

However, to be honest, if the question was just "which boss I would like to be", I would choose Lanza because he got to be 103, but that's just my personal preference; if ALL factors are to be considered, imo La Rocca would probably be the best choice.

Willie Marfeo to Henry Tameleo:

1) "You people want a loaf of bread and you throw the crumbs back. Well, fuck you. I ain't closing down."

2) "Get out of here, old man. Go tell Raymond to go shit in his hat. We're not giving you anything."