I've installed Open Solaris on 3 different laptops (hp nc6400, dell inspiron 300m, toshiba u205) and 2 desktops (dell workstation with quad xeon and sun ultra 20) and here's my take:
1) open solaris is a really cool idea and i am happy sun has taken this step forward
2) although it installs really easy, the lack of audio drivers (in particular for standard intel chipset) is upsetting. a tech guy at sun told me they are fixing this in the next release.
3) someone posted that it comes with codecs??? really ... the only way i thought you could play mp3's is to deal with fluendo $$$. i never got mp3's to work.
4) the package manager is REALLY nice, but much much slower than e.g. synaptic.
5) if you're used to linux, some things are really challenging in Open Solaris, for example, devices. In linux, it's easy to find your usb drive (e.g. /dev/sdb2) and mount from command line. pardon my general inexperience with solaris, but i found it impossible to sort through the many many many virtual dev that OS uses. long story short ... my quick and easy linux tricks don't work in solaris which make trouble shooting VERY difficult.
5) wireless was hit or miss ... on some laptops, no problem at all. on others - nightmare (i guess this is the case for linux too)
6) acpi (on laptops) is flaky, but same for linux sometimes too.
PROS) i like that sun is trying to give us a complete open source world: open solaris, open office, open jdk, mysql, netbeans, etc.. THAT in itself is so cool: to have one company trying to give you the whole integrated package. all these things together make for a really great laptop/desktop
CONS) your linux skills might not apply when troubleshooting and given x hours of free time in the day, you may not want to dive into solaris ... also, sun's customer support (even with my free trial of ultra 20) is horrible. be prepared to be tossed around to dozen's of customer support people, each of whom seem to know less than you do.
FINALWORD) give it a whirly-ding. it's a great experience and i think the more people that try/use/comment/fix open solaris, the better it will become. i just wish sun would have thought of open sourcing solaris 10 years ago when it could have grown up to be what linux is right now.