For your consideration, my adventure with getting LibreOffice running optimally on the KDE spin of Fedora. Not too hard :).
While KOffice and the Calligra Suite perform better on KDE (for obvious reasons) and I prefer their use for my own ODF needs, I've found LibreOffice still handles Microsoft Office documents the best, even ones that are saved in those terrible Microsoft OOXML-based formats. I use the term "OOXML-based" given even Microsoft Office doesn't strictly conform to their own ratified standard.
Method one: downloading from LibreOffice.org
For those wanting the latest bleeding-edge release, downloading the RPMs directly from LibreOffice.org is the way to go, and the good news is the RedHat integration RPM even lets KDE pick up the newly installed applications.
The downside is that the GTK+ interface seemingly doesn't inherit any theme, even if you've specified one in your KDE settings. The result is an otherwise usable office suite that looks even more out of place in a Qt desktop than usual. There may be a way around this, but for now I just opted for method two.
Method two: Fedora repos
For those using the default Gnome install of Fedora, you can simply fire up a Terminal and issue this obfuscated command:
% su # yum groupinstall "Office/Productivity"
I wish I could just as easily install office productivity into my brain, sometimes its hard to garner enthusiasm for writing reports and the like. But I digress.
The problem with this approach is it introduces a lot of Gnome dependencies I don't want or need on my beautiful KDE desktop, so I prefer installing each component separately. For example:
% su # yum install libreoffice-calc libreoffice-draw libreoffice-impress libreoffice-writer
Running this command didn't introduce many Gnome dependencies at all, leading me to think another LibreOffice application I don't use needs them. In any case, I fire up these applications and they look and perform as much like a Qt app as a GTK+ app with the correct theme can.
If you run LibreOffice (or even OOo) on KDE, I'd love to hear how you use it.