I upgraded to Gutsy RC last week, and I've really had nothing but trouble, and submitted lots of bugs (which is what you are supposed to do with a release candidate, but with only a few days left to go, I'm wondering how many of these are really gonna get fixed in time). Some of these may be particularly related to Kubuntu/KDE, and some might be due to not having a clean install, I don't know.
The upgrade tool failed — in fact I've never ever had a 'dist-upgrade' go smoothly, despite the advertising. In my case after the tool failed, I had to manually do 'aptitude dist-upgrade' 3 times before everything was finally sorted out. Dist-upgrading is simply not for novices. I guess the problem is that people do it so infrequently, and test cases are so massively time consuming to set up, that it is never properly tested in the real world.
The Ubuntu-packaged nVidia drivers disappear every time I reboot. It means I either have to use the open source 'nv' driver (and no accelerated graphics), or X fails to start and I have to manually reinstall a package.
Even when I get the nVidia drivers it working, I still have X crashing on me when using Compiz. It only happens when I'm doing lots of things at once — some changes in window activity at the same time as doing something in the background that is disk and CPU intensive (e.g. installing software). But this is still unacceptable for a default option.
Compiz-fusion itself is quite nice (I've found a combination of plugins that works very nicely, giving me a nicely animated 2x4 desktop, plus 'Expo' and nice Alt-Tab mechanisms, with all my normal shortcuts for moving windows around). However, KDE integration is pretty bad — whether I use the 'KDEWM' environment setting to start Compiz, or put something in ~/.kde/Autostart, I end up with lots of problems: the KDE window decorator dies at startup, and randomly dies at other times too; some windows that appear at startup, especially the prompt for the KDE Wallet, don't actually ever appear; using KDEWM, the 'Alt-F1', 'Alt-F2' KDE shortcuts don't work. The only safe method I've found is to do a manual 'compiz —replace' after my session is completely restored.
KControl and KInfoCenter were empty — thankfully the fix isn't too hard
My Input Actions (KHotkeys) were wiped out (thankfully the relevant config file was not emptied, and eventually by trial and error I found a workaround)
BibleTime crashes when you change an option for module display, which is a real killer for me. It also crashes/fails when you try to add/change side-by-side Bible translations to a window, which is equally painful.
What's left of the advertised benefits of Kubuntu Gutsy? Well, there is Dolphin — but I already had that before. There is 'Restricted Drivers Manager' — great, except that it completely failed with the nVidia drivers as described above. There is a newer version of strigi, but is no better than it has been in the past — it is alpha quality software really (things like the daemon refusing to stop etc, dying randomly, and the interface being extremely basic compared to Beagle. Actually, it currently dies whenever I tell it start indexing, so it is basically useless. And this problem reoccurs after purging the indexes and starting again, after indexing about 300,000 documents).
Then there is GDebi, which is quite nice, but I'm not likely to use it often. Amarok 1.4.7 is included in Gutsy but I was using that anyway from the backports repository (using apt pinning to ensure I only got the packages I deliberated upgraded). There is also the enterprise version of KDE PIM, which I imagine is quite good for some people, but the only thing it brought me was a bug in which events are not updated in the calendar. Finally, the OpenOffice suite has been updated to version 2.3, which may well have some genuine improvements - I haven't used it enough to tell.
There was one really good thing — 'Suspend' actually works on this non- laptop computer, for the first time. At least, it worked when using the normal 'nv' video driver — it didn't with the nVidia driver. I'm not hopeful that it will even if I get nVidia drivers properly sorted out. Which means that I'll either be choosing between the ability to have 3D accelerated graphics, and being able to suspend.
In conclusion — there is nothing so far in Kubuntu Gutsy that I would have upgraded for. If the bugs above aren't fixed soon, then I would definitely be far better off with Feisty, but I'm still hopeful that the guys at Ubuntu may be able to get some of these sorted out.
UPDATE: Ubuntu 7.10 is upon us, and none of the above are addressed. I'm wondering how difficult it is to downgrade...
UPDATE 2: Although nothing has really been addressed, I've discovered how to get 'Hibernate' and 'Suspend' working with nVidia drivers. Since I'm no longer rebooting, aand not even having to log in again, this has alleviated some of the problems.
UPDATE 3: Thanks to help on a bug report, I got my nVidia modules to stop disappearing, result! Some genius also got BibleTime fixed up (had to compile from source, but it was worth it). X crashing got worse — twice in 10 minutes yesterday — so I've abandoned it again until the bug is fixed. But my system is basically all working now, and both Hibernate and Suspend now work perfectly, which is a real time/power saver, so I'm happy again :-)