Solaris 9 is the last version to run on all
64-bit Ultras; Solaris 10 is
very impressive from a networking and virtualization standpoint (plus
ZFS kicks some serious ass) and is what you should be running if at all
possible.
So where's your line between 9 and 10? I just moved from a U1 200E to a U10 333, and
I stuck with
5.9 because I was concerned about usability on the U10.
I just inherited a U10 (400+?). I was planning on installing 8.
Is it wiser to move to something else? (I need 8 for Jaluna
cross-development but can keep that on my U1 if need be)