Mark Mayo lists his top 10 Solaris Installation Annoyances.
I'm not going to try and pretend that the Solaris installer isn't anything other than bad, but consider the following:
I've done thousands of Solaris installs over the last decade or so. I can probably count the number of times I've used the interactive installer on the fingers of one hand. No, I didn't like it much either.
The fact that most admins with a clue use jumpstart means that the interactive installer has received precious little attention. Even if the interactive installer was the best thing since sliced bread, I would never use it at work. That's not to say that the interactive installer can't be improved - it can, and must be.
I've not used a modern Linux installer (say, Ubuntu) but have used RedHat, Mandrake, Suse, Fedora. And I wouldn't necessarily say they're actually much better. Sure, they might look prettier, and feel slicker, but were often fragile (installer just bombs out) and unreliable (system all messed up afterwards). The Solaris installer might be butt-ugly and dog-slow, but produced working systems if you were prepared to suffer to the end. And if people are using interactive installers professionally, they need to get with the program and adopt some automatic provisioning scheme.
1. As for why it's slow, some work has been done on this. The biggest problem is that the distribution is compressed with bzip2. It goes way quicker if you swap out bzip2 for gzip.
2,3,4. Never happen if you use jumpstart.
5. I would argue against any attempt to change the default shell to bash. (Now, if they suggested tcsh, that might be received more favourably.)
6. Err, who on earth logs in as root?
7,8. We ought to chuck vi and vim and replace 'em with emacs...
9. Urrgh. Sendmail.....
10. Secure by default has finally made it into Nevada. But automation under jumpstart would normally knock out services you don't need.