During the installation, I've set my location to Oslo. This resulted in using Norway ubuntu mirrors in
/etc/apt/sources.list. These repositories were not usable for some reason I didn't want to investigate. On friend's suggestion, I've pointed the APT sources file to US mirrors and things started working OK.
I'm disappointed that, although they boast about fresh software packages, they only have tetex 2 in their .deb packages. I had to compile on my own tetex 3.
Another seirous criticism goes to default settings of applications. I've installed postfix in the "smart-host" mode. I was really surprised to see it was by default listening on all network interfaces! In FreeBSD, sendmail is installed and enabled by default (to allow local mail delivery), but it is listening only on 127.0.0.1. It took me 5 minutes to install postfix docs, find the option and fix it, but still - I don't think that this is a reasonable, secure default.
The most serious critic goes to stability. It froze on me twice in two days. Even with Windows XP I haven't had such experience in quite a while. I don't remember the first freeze, but the second is like this: I'm working in GNOME (trying it out), lock screen, return, and I can't do anything. Processor starts heating up (I hear the fan turning up to its max), after a long wait (~30sec) the password entry box appears, but I can't type in anything. I can see that the thing isn't really frozen (i.e. there is interrupt processing - e.g. the mouse pointer moves), but I can't even switch to console to log in and kill the X session. C-A-Backspace also doesn't do kill it. So I do Ctrl-Alt-Del and succeed in cleanly rebooting the mahcine.
OK, it is beta, preview, call it whatever you like. I would expect some applications to crash, some packages not really being set up the way they should. But falling apart in a way that I have to reboot the machine - sadly, comparable to Windows. Which have, in contrast, become remarkably more stable as of XP (on my former work I used to run them, without any trouble, for over two weeks without a reboot).
My last, application-related problem, was getting Thunderbird to work properly, after restoring the backup of my home directory. To add to the trouble, my accounts were enigmail-enabled with an older version of enigmail. It took me 2 hours of trial and error to figure out how to properly move my thunderbird profile over to the new OS. Start thunderbird on an "empty" profile, don't create any accounts or profiles, and copy from the old profile just the
prefs.js file and
Mail directory. Just in case, I've deleted all references to enigmail in the copied
prefs.js and everything worked fine. OK, this is hardly Ubuntu fault.
Not having something like "Archive accounts" and "Restore from archive" in the GUI menus to ease account and mail folder migration, I blame on the thunderbird team. Because unpacking the existing profile and using it with the new thunderbird and new plugin versions, simply does not work.
On the positive side, almost all hardware that I've had a chance to test at home is working perfectly. I didn't bother with 3D acceleration because I don't need it. Sound, USB stick hotplugging, even the wireless card, using ndiswrapper, is working OK. I didn't have the chance yet to try out the Ethernet card yet, but it is readily recognized on boot, so there should be no problems. I guess there should be no problems with other HW, either.
The only exception is that "small rubber thing between GHB keys" that serves as a mouse-replacement. This simply stops working in X after soft reboot. It works after coldstart, i.e. power-on.
Another nice surprise is Acrobat Reader 7 in the packages. I was really amazed about that! Software packages seem really fresh overall, save for the unfortunate tetex. Firefox 1.0.6 and Thunderbird 1.0.6. I haven't moved from 1.0.2 on FBSD because I was too lazy to compile it and fixes were appearing to frequently. I simply did not have the nerves to keep pace.
To conclude: I've migrated from FreeBSD 5.3 which is far from an OS targetted at desktop users, but I've had no problems setting it up. And absolutely no problems (stability or otherwise) running it. Although, to be fair, I was using only fvwm2 on FBSD, and I'm trying out the new GNOME on Ubuntu. As can be expected - more features, more bugs.
Overall, it's a nice system with a familiar Debian flavor. However, I would recommend that you wait for the release. This preview version is too much trouble in my experience.