I upgraded my Ubuntu box the other night. The process was pretty impressive. For one thing, it was significantly faster than an MS Windows or Mac OS upgrade.
The process started with "Update Manager" saying, instead of the usual list of updates, that there was a new release, and would I like it? I hadn't heard any horror stories in the couple of days since the official release, so why not?
After the packages were downloaded, I was told that I'd modified a couple of files. The NTP configuration, for one. I clicked for the diff and saw that the default configuration now has an NTP server. So that's one of my Ubuntu 5.10 complaints fixed. The other conflicting file was my gdm(1) configuration, but that diff was too complicated for me to bother with, so I took the maintainer's version there too.
The desktop background image changed while I was looking at it, which was a bit weird. I'm used to other OSes taking me out of the normal OS while it's being upgraded. But everything went smoothly enough. The new background image is yet another stinky brown turd lagoon, but this time at least there's a non-brown option. It's a picture of a small green bush called Dawn of Ubuntu, and it's okay to look at. My preference for GNOME's default Clearlooks theme over Ubuntu's festival of orange and brown was remembered.
I don't understand why they don't just use the default GNOME stuff, though.
As for installing Sun's Java 5, it has become a little easier. Choose "Add/Remove..." on the GNOME "Applications" menu, check "Show unsupported applications", and type "sun java" in the search field. You can then select and install Sun's Java 5 JRE (but not the JDK, which is a shame).
The license agreement is presented as a very respectable-looking dialog, but there's nothing equivalent to the update-java-alternatives(1) step, and GCJ remains the default, which is rather unfortunate. (I can understand not changing the default automatically if the package had been installed as a prerequisite, but if it's been installed by direct user intervention, isn't it likely that it's the version they prefer?)
Anyway, the Sun JRE installation process is quite a bit more convenient now, though I'm not sure what mechanism an application is supposed to use to choose an appropriate JVM. It seems to me that the update-java-alternatives(1) approach is fundamentally flawed when compared to something like JNLP that lets you say "I need 1.5 or better". A global default is perhaps sometimes useful, but not nearly as useful as being able to specify your exact requirements. As it is, I guess we're going to have to hard-code the location that Sun's 1.5 JRE gets installed at.
I've been able to get rid of my built-from-source bzr(1) in favor of the 0.8.2 package, but other than that and the things mentioned above, today is mostly like yesterday. Which is I suppose a recommendation of sorts, if not a particularly glowing one. Seen from the Debian perspective, though, Ubuntu 6.06 is like Debian testing/unstable but without the random bits of breakage every time you upgrade.
Unlike the Mac OS 10.3 to 10.4 transition, I haven't yet noticed much breakage, or that I'm being drowned in fatuous features. And Ubuntu 6.06 didn't cost me $120 or take forever to install, either.
[An earlier version of this post mentioned update-alternatives(1) instead of update-java-alternatives(1), but David Herron rightly pointed out that it's not generally a good idea to change one of the Java alternatives without changing all of them, and update-java-alternatives(1) makes that a bit easier.]