Imagine my joy to find that, though the keyboard works well enough for me to log in, I can't type once I'm at the GNOME desktop. No key on my wired aluminum Apple keyboard does anything. (The test machine, of course, had the older white plastic keyboard.) The machine itself is a PC, not a Mac, but it seems someone broke the kernel driver. Launchpad bug #201887 seems related, and showed me the workaround, but I haven't once touched the numeric keypad in the keyboard's whole life, and rebooted to check that the numeric keypad has nothing to do with it by very carefully ensuring that neither my pudgy fingers nor my mouse's cable nor my cat were anywhere near the numeric keypad as I logged in.
Anyway, if I ssh in from another machine, I can use this to fix the problem:
sudo su -
echo 0 > /sys/module/hid/parameters/pb_fnmode
This, I'm told, basically turns off all the dodgy code in the kernel module.
Judging by the bug, they knew about this before the release, but didn't bother to mention it in the release notes. Next time I ask myself why I have more than one computer, remind me that the answer is "so I can search the web for workarounds when one of them is broken".
The second most annoying problem is that sleep ("Suspend") is broken. It worked fine in 7.10 on my desktop (Intel DP35 motherboard with a Core 2 Quad) but won't wake on 8.04; the power light comes on, but nobody's home. Sleep never worked on my other machine, the one I tested on, so I didn't notice this until it was too late. That's an interesting question, actually: do test releases tell you more about crappy old hardware than they do about the newer hardware people are using for their day-to-day work? Or do other people actually buy two of everything, so they can run a properly scientific test?
Other problems? The weather applet has reverted to Fahrenheit, which might be useful for my dead ancestors (but only ones I never met; my grandparents were happily using Celsius before they died). "vbetool", a program I'd never heard of until today, crashes on login; a web search says "vbetool uses lrmi in order to run code from the video BIOS". Which is probably more useful than it sounds, if you like the power-saving states of your display. Speaking of displays, I was reverted to the free driver for NVIDIA cards, and the MP3 codec needs installing again. (In both cases I feel like I've already made my decision there, and shouldn't be made to repeat myself until there's a suitable alternative.) I don't like Firefox 3, either, but I might get used to it (or it might improve when it's no longer a beta; what's a beta version of the web browser doing in a long-term support release of an OS anyway?).
Anything positive to report? The graphs in system monitor (the ones you see if you pop open the detail window) are slightly prettier now, but I never used to look at those anyway. Other than that, you wouldn't know it it's not 7.10. I think I've said before that 7.10's pretty good. I use 6.06LTS at work and really feel a need to upgrade there, but there was no real reason for me to move from 7.10 to 8.04. And, as it turned out, doing so was a mistake. If I could go back in time, I'd stick with 7.10 for now, and I'd probably try testing with a LiveCD on the machine I care about rather than a real upgrade of a different machine before clicking the "Upgrade" button.
Now, if you'll excuse me, it's time to add a line to rc.local so I don't need two machines just to log in...