1. Bonanno
2. Lucchese
3. Colombo
4. Gambino
5. Genovese

Bonanno family is the most desperate. Looking at who has been made into the Colombos and Luccheses since the mid 2000's, Lucchese would be easier while the Persico family inducts blood and relatives more. The Gambino family with the zips have made it tougher to be made, while the Genovese family raised the requirements as well. One of the biggest things is what Serp posted above. It all depends on who you are around, grew up and who the Boss is of that family.