This document is of mostly historical interest now...

As of Thu Jan 18 18:13:31 PST 1996, UCI/OAC/DCS (yes, that's the chunk of the university I work in) looks after 116 Solaris 2.x machines - 9 Solaris 2.3, 83 Solaris 2.4, and 24 Solaris 2.5. On the whole, they appear to be doing quite well.

Following, is a list of reasons why you should shift to Solaris 2.5, instead of sticking to SunOS 4.1.x. The reasons provided are almost entirely technical - net.politics, and seeming cool to your buddies, are ignored.