I downloaded the OpenSolaris cd image and tried to boot it up in an virtual machine using Virtual Box. First I tried 256mb of ram, but with that it just got stuck up during the bootup process. With 512mb of ram it runs but it's still slow and sluggish compared to Ubuntu or other Linux distros running in a virtual machine.
I have 2GB of ram in my system, and it eats up around 500MB with compiz and stuff running Ubuntu 8.04 ( hardy ) ...
Other than the system requirements OpenSolaris looks quite polished and I quickly fired up the package manager to upgrade the installed packages ... but oooopppsssyy! ~ 1800mb to be downloaded??? are you kidding me????
Well, I won't download 1800mb of stuff, no way, that never gonna happen.
The "Virtual Box" additions are not available for OpenSolaris so it's really annoying when you wanna do something you need to click inside the virtual machine window, then press the host key to release it, etc. quite annoying.
I'll leave it installed for a few more days, just for fun ... I also found out that there is Nexenta a distro built around the OpenSolaris kernel with lots of open source software. It's really interesting, and I'll have to check it out in the near future ...
As a conclusion ... I'm a developer myself so I could build my own stuff, though I won't drop my Ubuntu for OpenSolaris yet, but that may change :)