Sorry but I disagree with you guys. Official nightlies just mean there's a build bot/Jenkins, which compiles nightlies (CM) or weeklies (FXP). Therefore, it doesn't make sense that official nightlies are more stable. You could go and build it yourself, but your build wouldn't be different.
Concerning FXP builds, you have to ask Varun or Jerpelea. I don't think there are (m)any differences though...
Oh and FXP is a team consisting of CM devs and maintainers.
If you like my work, please feel free to donate. The money will be spent on a new build server...
And in case you want to report a bug in any of my ROMs, please...
don't report issues that have already been mentioned.
use DevDB whenever possible. This keeps the threads clean.