We prefer to use packages available in the Debian/Ubuntu repositories. They have usually gone through lots of testing, comply the DPL (I mention this in general), management of the package is simpler and less error prone as its just another package managed by APT, and regular security updates are available and can be applied automatically without user interaction.

With that said, Ruby Enterprise Edition looks very interesting. If you (or anyone in the community) could do some testing and document your experience, it would push this issue forward.