Personally, I am holding off on KDE 4. Yesterday, I checked out the KDE Four Live disk with RC2++ and to be frankly honest, really let down.
Some of the new changes, seem cludgy. Such as the menu, giving no easy and quick way to drop back folders, just close it entirely and reopen (which seems a bit silly), or click, click, click, click on the back arrow. This is annoying to me, because sometimes applications get their shortcuts automatically installed to a location I might not think it should be, and so when I'm hunting around for them to find out where the folder is, things slow down (the search thing is nice, but I like to know where stuff is too). Or oops, I clicked the wrong folder, and unlike before, I cant just move my mouse a few pixels over to highlight what I meant to go after to change, I have to move around and click some more. Yeah, this is minor, but, the new kmenu was supposed to make things faster and easier, where as this is a bit of a regression.
I WANT TO BE ABLE TO CHANGE THE KICKER! I HATE, HATE, HATE a big fat kicker. Yeah, I know it is "Plasma" now, but why the fuck should you REMOVE functionality? Also, I liked my LCD looking clock! I had my theme how I liked it, thin kicker, bland grey, Clock with LCD look, Plastik and Keramik mix on the theme. It was small, bland, and utilitarian.
Control Center. How do I start with this. It looks like shit. Takes up WAY too much screen real estate for what it does. It is kinda similar to the Windows Control Panel and OSX System Preferences, BUT GONE WRONG! Also, with the tabs, shit is more difficult to hunt down.
Basically, I would like some of the old ways brought back. Old style Kmenu, with a search bar at the bottom would be nice. Normal Kmenu look, but when you search, it converts into the List style. Old style control center. Ability to make the new plasma kicker as customizable as the old kicker. I had been looking forward to KDE4 for a while, even been using the 3.5 backport of Dolphin for months, but with some of the things I had issues on, everyone kept reassuring me that "oh, you can make it look how it used to". If that is still the case, let me know how.