It depends what you define as being stronger. Both families are more stable, definitely so for the Lucchese's. There seems to have been a period of regrouping and stabilization in the past decade or so.

Crea is having a good run. I don't know as much as most on here but from what I read he's a powerful guy with a ton of respect. For the Gambino's you have quite a pretty secure hierarchy with quite a few powerful guys. The New York families in general (perhaps with the exception of the Colombo's) realise that you have to adapt. It's the year 2014 and you have to live as if it is. Take your medicine with some shit, keep the violence down and as long as you aren't stupid then you can earn.

It'll be interesting to see what happens in the next decade though. You would imagine more and more time will be spent fighting terrorism, and with the number of agents tackling LCN already diminished you wonder if the families try and exploit that somewhat. But generally, relative to how unpredictable LCN can be, the Gambino's and Lucchese's aren't doing too bad.