I've tried many different JB roms and I've pretty much liked all of them. I tend to like roms with more customization options. Of course, they need to be stable, but even some no names I tried were pretty much solid. Recently I've pretty much run either AOKP, Euroskank, CM10, JBSourcery (although 2.1 was a disaster that the devs admitted and quickly fixed in 2.2), or CNA for about a week at a time. That said I've tried about every rom on galaxynexusroms at one point by now. I've been running CNA 3.5 with Franco M5 and it's been flawless, but so have many others. JBSourcery has to take the cake for having the most options built in (as in being able to flash mods/icons/fixes from within the rom manager), but I found flashing this or that myself here and there more fun. Setup is snappy and painless with the help of Google, Nova, and MyBackup Pro. Make a nandroid and flash away without fear. I suggest looking through the rom/kernel options etc. before bothering to setup your phone.