Notable for still maintaining some level of SPARC support.
On a personal level I'm impressed and fascinated by the fact that apparently one man created and has maintained an illumos distro for many years;
* making an OS distro at all is hard
* making an illumos distro is harder (less precedent to work from, and IMHO Sun didn't do a great job documenting things if you weren't inside Sun)
* making a different distro is harder; this isn't an OpenIndiana rehash, AFAIK it's mostly novel
* and of course maintaining it for so long is a huge undertaking
One of the reasons for creating Tribblix in the first place was that there really wasn't any documentation on how OpenSolaris (as was) was built. I wanted to understand that, so had to work it out essentially from scratch. I soon worked out that there were ways to do it better, and Tribblix is still here something like 15 years later.