OI uses IPS packaging, which is the same packaging used by Solaris 11 (some find it over engineered). Tribblix, on the other hand, is also an illumos-based distro but is based on Solaris 10 (and prior’s) SVR4 packaging which is managed via a utility called “zap”.

Both are good distributions, but I strongly encourage you to try Tribblix if OI is problematic; for whatever reason the latest OI installers do not seem to include the same amount of driver support as Tribblix, in my experience.