So, on a lark, I decided to upgrade my laptop last night from Xubuntu 8.04 (Hardy Heron) to 8.10 (Intrepid Ibex). Smoothest, most flawless upgrade I've ever done. Slick as I'd expect from a Debian derivative. "aptitude dist-upgrade", and done. Then I noticed that Kubuntu Intrepid was including KDE 4.1 instead of 3.5.10 as its desktop. Nice. I'd been wanting to check out KDE 4.x anyway.
Now, don't get me wrong, I never minded KDE 3.5 - it's just that it didn't really wow me. I had my own way of working, forged from years of using OS/2, Mac OS, NeXTSTEP, Windows and several breeds of Unix desktops, and KDE 3.5 just got in my way when I tried to work like that. So I usually used Xfce instead. But I was feeling froggy - so I tried it.
Switching was easy. I already had the 'universe' repositories selected (oh, and this can be done graphically in Hardy/Intrepid, BTW - no more editing sources.list unless you want to). All I did was pull up a console and do 'aptitude install kubuntu-desktop. If you hate/fear command lines, you could do this with Synaptic too. Then I just chose KDM as my default login manager (an optional step, BTW - you can use KDE with GDM if you want), logged out, logged back in, and BAM! Instant KDE desktop.
Now, I had a few gritches straight away - for some reason Kubuntu's default KDE config omits a lot of window decoration themes and Qt styles, which sorta narrows your options. This might not bug most people, but while I like the 'Oxygen' widget style, the 'Oxygen' window decorator leaves me cold. So I fired up Adept, the KDE apt frontend (which, by the way, is clunky, but that's not KDE's fault specifically), installed a few more and configured. Then I swapped around some keybindings to fit what I've come to expect (and to use the Windows key, so my ctrl+foo combos can be free for apps) - but that's optional, the defaults are sane.
Well, KDE 4 looks sharp. Take everything they did right in Windows Vista, and a few ideas from Mac OS X, plus a few more that are decidedly Unixy, and there you have it. It took me a second to get oriented, but I quickly fell into the KDE way of doing things. I figured out how to add a second panel easily enough, and how to add application launchers, or files to a panel. What wasn't immediately obvious, though, was how to put launchers on a specific panel. Not obvious, that is, until I put my mind back into the OS/2 paradigm, which is what predominated back in KDE 1.0. All you've got to do, is drag the app to the panel. Obvious. Too obvious, actually. Maybe slightly counterintuitive to a Windows user, but Mac users will figure that one out quickly. The 'right-click, select option' paradigm is much less set in the heads of Mac fans.
Plasma, the new desktop manager, is interesting. It's shades of the Mac OS X Dashboard (and can even use HTML-only OS X Dashboard widgets). Where it's a bit of a departure, is its desktop handling. In Windows, Mac OS, GNOME and previous versions of KDE, the desktop consists of files stored in a Desktop directory, plus sometimes some "magic" icons that don't actually live on the filesystem anywhere. In KDE 4, you instead get a dashboard widget, called a Plasmoid here, that offers a 'folder view' - basically an always-open file manager view into an arbitrary directory, which by default is the "Desktop" directory in your home dir. On the desktop itself, you can place files or application icons - but if you do, it works like it does in RISC OS or CDE. The file or app isn't actually copied or moved anywhere, it's just a pointer to it on the desktop. Since I'm a long-time ROX-filer user (and may not give it up yet!), this is just right for me. Besides, I've never been a fan of desktops festooned with zillions of files everywhere. If you really can't live without this functionality, KDE 4.2 will include the capability to "maximize" the Folder View plasmoid, allowing it to function as your entire desktop. This will restore the KDE 3.5-style icon handling.
The new Kwin includes OpenGL desktop compositing. It can use either the Xrender extension, or OpenGL directly. In my case I'm using OpenGL because that was the default, I haven't really tried the Xrender option. Kwin has an effects engine similar to what Compiz offers, but in my experience it's a lot faster than Compiz, and generally feels less balky. In a word, it's slicker than an eel in a barrel of snot. It's so slick, in fact, that I'm seriously tempted to switch to Kubuntu on my main workstation when I get back. Or maybe I'll try out Gentoo's KDE 4.1/4.2 stuff and see how it is.