Illumos-based distributions are currently not fully mature
As a sysadmin I'm used to my Unixes having certain amenities and conveniences. I've come to accept that any non-hobbyist Unix distribution that wants to be taken seriously (especially a free one) will have things like an announcements or security updates mailing list, a bug tracker, at least a somewhat visible security contact point, and documentation about all of this (along with things like how often security updates are made for any particular release and indeed the release policy). Some form of signed or verified packages are state of the art, along with the key infrastructure to support them.
While some of the various Illumos distributions are clearly hobbyist projects that you can't expect this from, some are equally clearly aspiring to be larger than that (swank websites are one sign of this). But, well, they don't seem to have pretty much any of these amenities that I'm used to. Does this matter or am I being too picky? I think that it does.
(A certain number of the pretty websites started looking a bit bare once I started following links.)
The surface reason is that these things are important for running production systems; for example, I'd really like to know about security fixes as soon as they're available for the obvious reason (we might not apply them, but at least we can assess the severity). The deeper reason is what the omission of these things says to me about the distribution's current audience. To put it one way, none of these things are needed by insiders who are deeply involved in the distribution already; they know the security update practices, they follow the main mailing lists, and so on. All of the documentation and so on is for new people, for outsiders like me, and the less it exists the more it feels like the distribution is not yet mature enough to be sensibly used by outsiders like me.
(There are some bits of this infrastructure that you may want to think about carefully beforehand, like bug trackers. But announce mailing lists are trivial.)
I'm sure that all of this will change in time, at least for the Illumos distributions that want to be used by outsiders like me. But right now I can't help but feel that Illumos distributions are not yet fully mature and up to the level of FreeBSD and modern Linux distributions (regardless of what the quality of the underlying OS is).