Yeah, the compatibility element is really important. I've been doing tons of research around illumos, SmartOS, etc., lately and I'm hoping to deploy it in some projects soon. DTrace knowledge becoming properly portable across systems is a great thing.
I've been very impressed with illumos from a technical standpoint, as a Linux admin for over 10 years whose never really had cause to seriously wander into the now-esoteric "proper Unices". Combination of the massive relief that is ZOL and the disastrous aftermath of the [ongoing] Linuxland "container revolution" got me looking for more.
But before I commit to illumos in a substantial way, I'm trying to understand the social dynamics around it more, and whether the community is essentially just crossing fingers and hoping that Samsung doesn't shutter Joyent, as they've done to other open-source acquisitions, especially as alternate distributors like OmniTI have bowed out. So I've been doing lots of sleuthing and trying to piece together some of the drama behind this whole ecosystem.
A lot of the momentum on SmartOS seems like it gave out during the first half of 2014 when Brendan and many other important Sun alumni left Joyent. Bryan Cantrill addressed this in an AMA by saying that he thinks some of them just tired of fighting an uphill battle (which, IMO, is totally understandable and actually doesn't seem like it's too far off the mark), but the close timing with which basically everyone except Bryan Cantrill made this decision makes me wonder if there was some internal event at Joyent that signaled a need to head for the hills.
This theory is inflamed by Brendan's apparently complete abandonment of illumos and the tone he takes when he addresses illumos/Solaris, frequently telling people to avoid it and that Linux is much better nowadays. He didn't leave Joyent and continue to extoll the virtues of illumos or SmartOS, even though his farewell post says that his high opinion on the value of illumos tech hadn't changed. He left Joyent and seemed like he was relieved that he could finally let it all out and talk about the futility of illumos/Solaris.
These days, he frequently leaves comments saying things like (paraphrasing here) "You could use [illumos distro], but I don't know why you would." and "We'd be in trouble if we picked the wrong OS at big companies like Netflix, and none of us are picking Solaris."
It just feels like there are pieces of the puzzle missing here. I get that there is a long and storied history to illumos (as Cantrill points out in one talk, the codebase is older than he is!) and that everyone brings a lot of personal perspective and emotion to it, so I don't expect there to be a simple answer per se, but I just want to feel like I've got my arms more around it.
SmartOS really does seem like a saner system for people who want things that work without constantly fussing, but I don't want to become dependent on a system whose future appears to hinge completely on Cantrill's continued employment with Joyent, especially post-exit, as he is likely bound by golden handcuffs.
Node.js is another Joyent puzzler with its own long and tortured history (though obviously, much shorter than Solaris/illumos). It's strange, imo, that they were ever really involved in that in the first place. I can only guess that they were quick to snatch up Dahl and ride the wave before Google et al could get their wits about them and establish control over that segment, but maybe it has more to do with Joyent's relationship with web publishing via TextDrive, I don't really know. But if SmartOS weren't otherwise so charming, its integration of Node.js for system control scripts would seriously put me off.
Disclaimer: I have no idea what I'm talking about, I wasn't there, I don't know any of the participants involved, and I'm not trying to assign any particular feelings or values to anyone. This is just my read of the ecosystem and dynamic from reading stuff on the internet, and it is very likely wrong. Corrections are welcome.