I don't think anybody who likes the minimalism of Gnome is going to feel entirely at home in the configuration heaven of KDE, and the other way round. However, this is a matter of taste: I prefer Gnome's minimalism, but if you enjoy configuration options, you'll enjoy KDE. I've been trying the latest Debian beta version from a Debian Wheezy Live USB available now.
The last time I tried KDE, the Task Manager icon previews were not working with my graphics card; now they are. This was the main feature I wanted to take a look at.
I've been using Windows 7 quite a bit recently, and the similarity is obvious. In KDE the default setting is not to group windows, but this can easily be more changed. I like this way of switching between windows. The GIMP's modal windows don't behave well with Task Manger- they go off and do their own thing, which is annoying, but Libre Office behaves well.
The main menu will also be familiar to Windows users.
The default theme looks good, although Iceweasel need the Oxygen theme to blend in.
This is certainly a desktop I could live with. It will appeal to anybody familiar with Windows 7, as well as Linux users looking for a very configurable desktop.
I have to say, it doesn't seem like a very lightweight desktop environment. I can run a Live USB session of Crunchbang and hardly notice I'm not running from the hard drive, but with KDE the laptop fan was blowing frequently, and the computer locked up a couple of times. I don't know what it would be like installed, but I suspect not too zippy on this laptop's meager 1G of RAM; should be fine on more modern machines.
A more lightweight desktop for older machines (perhaps more appropriate for this computer) is XFCE. I've been using the Squeeze Live USB recently and have just downloaded the Wheezy version, which I'll be comparing and reviewing tomorrow.