Applications for your desktop
The cool thing about software built around either GNOME and KDE is that that they can by and large be used on either desktop environment. Yes, it also means installing the missing libraries for the alternate desktop environment.
But the end result is that I can run amaroK in GNOME or Banshee in KDE (tested with KDE 3.51). Still, it's generally best to stick with the software built for the desktop it was designed for.
But enough about interoperability of software between desktops. Which out-of-the-box desktop experience provides the best software?
Let's examine some common software examples.
KDE's Kontact vs GNOME's Evolution
Out of the box, Kontact offers more functionality while Evolution is frankly better suited to an enterprise environment using MS Exchange servers.
So while Kontact offers baskets, RSS, hyper-linked contacts and more, Evolution will allow me to connect to my workplace Exchange server without the need to rely on IMAP email. This is a win for me and others in my position.
On the user interface side of things, Evolution is a dead simple application to use, from setting up new email/calendar/contact accounts down to daily usage. There's nothing confusing about the Evolution software whatsoever.
On the flip side, KDE's Kontact software bundle is not a mere single application. Rather, its a grouping of mis-matched software designed to fit into a single PIM (personal information manager) exoskeleton.
While the Kontact setup is easy enough, there is simply more "fluff" provided than what most people really need bundled into a PIM. And this is not even considering the lack of "real" MS Exchange support, as supporting half of it while depending on IMAP email doesn't count.
KOffice vs GNOME Office
Neither desktop environment office suite holds a candle to Open Office on the word processor, spreadsheet or presentation software front. KOffice does, however, offer better project management software solutions in the KDE bundle.
The GNOME Office suite provides a real label maker option. So in the office suite category, it's a bit of a wash as to which comes out ahead.
GNOME's Epiphany vs KDE's Konqueror
I expect to get some static for this comparison, as Konqueror is more than a mere web browser. But I would also point out that from a usability standpoint, Konqueror stinks.
On the GNOME desktop, the user is given Nautilus for file management and Epiphany to handle web browsing. Each solution is simple and straight forward...without trying to be "all things" simultaneously.
Usability is different for everyone
I accept that I haven't changed anyone's mind as to which desktop environment provides the best user experience. Each of us has to figure that out for themselves. And considering the fact that today's Linux desktop has more desktop environments than GNOME and KDE alone, each of us needs to use what works best.
But I would ask each of you to consider this one thought. Think of a brand new user, one who is looking to try Linux for the very first time. I would say that KDE is honestly not the most logical stepping off point. Just some food for thought for the next time you're recommending a desktop environment for a new Linux installation.