I've got a 333 MHz Ultra 5 with 256 MiB. I've installed Solaris 10 on it to learn more about Solaris, but after speaking with another Unix admin I'm thinking that maybe 9 is a better option for me on this hardware. He says that 10 uses a lot more memory, and the biggest updates are optimizations for Java. Since I don't really have an interest in Java (at least in regards to this box), perhaps I'd get more out of it by downgrading to 9. Another perk would be the ability to make use of the SunPCi card in it. I won't be running a desktop...normally headless and ssh in only.
I'd like to get more opinions on the subject. Should I go with 9 or 10 given my specs and needs?
Update: OK, so you've convinced me to "downgrade" to 9. How painful is that going to be? Will the installer balk at the presence of 10, or force me to reformat?