Got mine today, thanks Sun. Too bad this'll never run on my SPARCstation 4.
Take it from me, I was a Solaris admin in a previous life. Solaris is rock solid, and now the x86 version is finally on par with SPARC.
No Linux distro can touch Solaris in terms of reliability, this is an enterprise grade operating system that you'd use when it absolutely, positively, can not crash. Thats not so important on the desktop, but that was never where Solaris's strengths were.
Just don't use CDE, JDS is pretty good but it might not be the default desktop.