Just installed the newest KUbuntu with KDE 4, and I noticed a few hang ups already.
1> Not thinking I uncompressed a file onto the desktop thinking it was going into a folder. It didn't, and suddenly I had 50 icons on the desktop. YOU CAN'T CLICK AND DRAG TO HIGHLIGHT THEM ALL! NOR CAN YOU HIT CTRL OR SHIFT WHILE CLICKING! I had to click the red X to the right of each icon to make then "delete"... or so I thought. Doing so just deletes the ICON. Go into your home folder and look in the folder Desktop... *all* the files are still in there, not a single one is deleted.
2> Playing around I removed the clock from the "system bar". I am unable to find a way to get it back. I re-created the widget, but have been unsuccessful in finding a way to re-dock it.
3> When you do the add/remove to install programs, I'd say 90% or more DO NOT show up in the "start menu". If you can remember the name of the program installed and type it in at the top, it will come up, but there is no ICON in the list.