...and it ain't Free software
As for daily workstation use, examine the applications that your business will be using in Linux. Weigh in how many of them are built for KDE. Customization per workstation aside, most offices will do well with KDE installed, but may fall back on GNOME based personal information managers such as Evolution over Kontact.
The details of their rivalry are not relevant here; what matters is that in the beginning GNOME was clearly perceived as the saviour of the free software movement, with de Icaza as its knight in shining armour, which is rather at odds with a current widely-held view on his place in the hacker pantheon.
The point here is not to take sides on this question, but to demonstrate the amazing and pernicious effects of Microsoft's recent engagement with the open source world. The growing tensions between the KDE and GNOME camps are just part of that: another facet is the split of companies into those who believe that intellectual monopoly deals with Microsoft are a good idea (Novell, Xandros, Turbolinux) and those who do not (Red Hat, Ubuntu, etc.).
The result is a growing schism that can only serve Microsoft's interests. Unfortunately, this is one area where we don't have a choice: we need to heal the rift. The question is, How?
In the recent accusations that the GNOME Foundation has been supporting Microsoft's OOXML format at the expense of ODF, KDE has been presented as a counter-example. Based on a KDE News article, Richard Stallman suggested that "major KDE developers" had announced "their rejection of OOXML" and urged GNOME to do the same. More recently, a widely linked story on ITWire used the same article to declare that KDE has taken a "principled stand" against OOXML. However, if you go the source, the story is more nuanced than these claims suggest.
While the GNOME Foundation media spokesman Jeff Waugh claimed recently that Miguel de Icaza has no official role in the GNOME project anymore, it is common to see long posts from De Icaza on the Planet GNOME website. This site is meant for GNOME developers.