The trouble with most comparisons between desktop Linux distros and Windows is that they are written from the perspective of someone who is comfortable enough with a PC that they can undertake a feature-for-feature comparison in the first place.
Consider the following statement:
It all compares pretty favorably to Windows's Add/Remove Programs system, which should be familiar to everyone reading this.
If you believe that most of your users are, in fact, comfortable knocking around Control Panel, then the informal benchmarking in InformationWeek's Serdar Yegulalp's head-to-head comparison of Ubuntu Linux and Windows Vista should give you a fair idea of what your business could expect in an OS migration.
And even if your users get lost just trying change time zones on their system clocks, there's plenty of useful info in Yegulalp's detailed and measured walkthrough on some of the challenges your support team will face with a move to Linux -- even a user-friendly flavor like Ubuntu.
I was most struck by Yegulalp's conclusion that Ubuntu wins the install test, primarily because you can run a reasonably full-featured instance of the OS from a boot CD without wiping down your hard drive. That's a real plus, particularly for a small shop without a big test lab.
Migrating to the Thunderbird e-mail client (Ubuntu's druthers) sounds like a nightmare, but then again what e-mail migration isn't? I was more taken with this assessment of Ubuntu's hardware management capabilities:
The most common types of hardware and usage scenarios are handled the best, but the further you drift from that, the more complicated it gets. At its worst, Ubuntu's way of dealing with hardware often involves manual hacking to accomplish things that ought to be trivial (and in Windows usually are).
Another red flag for most businesses: Yegulalp's conclusion on compatibility issues between OpenOffice and MS Office:
... if you're considering moving to OpenOffice from Office and working with existing files, make sure the documents you want to work with can be read first.
Granted, Microsoft's diddling with open document standards efforts is a major pain -- note, I didn't say surprise -- but businesses have to be able to use Word and Excel docs. Period.
Yegulalp, a self-professed Windows fan, is about as fair and balanced as you could hope for in comparing Ubuntu and Windows. In fact, the Linux distro wins many of the head-to-head comparisons, and more end in a tie. Clearly, Ubuntu comes out as a perfectly usable OS -- for somebody who knows what they are doing.
If that's not how you would describe your users, the piece could be a good conversation starter for your support team. It's certainly inspired me to do my own tire-kicking via that live disc option.