I really dislike the new KDE "kickoff" program launch menu; but at least the KDE developers had the good sense to keep the "classic" style as an option (which I discovered last year).

When I had a task bar on each screen, I added some shortcuts to my most-used applications. Since I now have a single taskbar for both screens, it's getting crowded, so I decided to put icons for those applications on the desktop. That's when I discovered that, regardless of which virtual desktop you add the icons to, they always appear on desktop 1. And only on desktop 1. That, to be blunt, is spectacularly useless.

The good news is, the developers have added a new category to the launch menu: "Favorites." And they've made it easy to add applications to that category (right-click on the application in the launch menu, and select "Add to Favorites"). That, at least, appears on every screen. It's three clicks now, instead of one, to launch my most-used apps, but until learn something clever with the taskbar, it will have to do.

I customarily set up my system with four virtual desktops, and give each a different wallpaper for quick identification. By default, KDE 4 uses the same wallpaper on all virtual desktops. Doing some on-line research, I finally discovered that this can be fixed in System Settings > Look & Feel > Desktop > Multiple Desktops, by selecting "Different activity for each desktop." How I'm supposed to deduce that "different activity" means "different wallpaper" is beyond me; another flub.

Similarly, the default is for the taskbar to show every program running in every virtual desktop, not just those tasks running in the currently active desktop. Very bad: I use the desktops to organize my tasks, and during the course of a work day can have 12 or 16 programs open. More on-line research! This site gave the solution: "Right click on task bar, select: 'Task Manager Settings', then select 'General' tab, and check: Only show tasks from current desktop"

Speaking of tasks and desktops: I'm used to using middle-click on the mouse to see what tasks are active on all desktops. That no longer works.

I recognize that laptop users may prefer the big blunt mouse cursors in the "Oxygen" theme, but I think they're ugly. In theory you can fix this in System Settings > Computer Administration > Keyboard and Mouse > Mouse > Cursor Theme -- and there's another flub, because why this isn't in "Look & Feel" is a mystery to me. But it's pointless, because KDE doesn't retain your new setting -- it reverts to "Oxygen" on the next reboot! More on-line research. I found a workaround, which basically says to rename the default theme to some name that KDE can't find:
cd /etc/X11/cursors/
sudo mv oxy-black.theme oxy-black.theme.disable

But hey, it's not all bad. I like the new Device Notifier (taskbar widget that tells you when a removable device has been added). The old Notifier put an icon on the taskbar for each removable device...and I have several such devices. The new Notifier is a single icon, and pops up a window when a removable medium is inserted or removed. Nice.

And I really like that KDE 4 includes an Updates notifier (to tell you when there are updates available for your installed software). I liked this when I was (briefly) running a Ubuntu box with the Gnome desktop, and I think it's a very important addition to KDE.

And I must admit that many of my gripes involve my having to change habits that I'd grown comfortable with. There are options or workarounds for most of my desires; and as for the remainder, I expect that in a few weeks I'll be used to the new way of doing things.