Production-grade FreeBSD 8 is released, and I have found FreeBSD more and more attractive as the OS of choice for my home server (as compared to OpenSolaris). Slashdot has a comprehensive coverage for it here with reviews, upgrade instructions, and screenshots.
So far I have not seen much development in OpenSolaris: the latest snv_128 snapshot cannot even boot on my amd64 system, so i am stuck with the 2009.06 of OS.
FreeBSD has added some interesting features, and ZFS is one of them. Unfortunately FreeBSD only supports up to version 13 of the ZFS, while my data is stored in version 14 format and this is an issue. Any slight mistake in migration will see all my data gone, which is something I hate to see happening.
I am still considering the relative merits of migrating to FreeBSD, the adding of more and more GNU tools and greater Linux compatibility has made this Unix quite a strong contender as desktop OS.
On the other hand, my current OpenSolaris setup is working properly as a file and general purpose server. I have spent more and more time using it as opposed to my Windoze machine nowadays. So I have to give OpenSolaris due credit for its stability and performance.
BTW, there are movements to put Debian on the FreeBSD and OpenSolaris kernel, though these two ports don't seem to have much development nowadays.