Some points
I wholeheartedly agree with Morely Dotes points.
I don't expect my wife to install an OS. I install Ubuntu Linux only because it has been difficult to buy a PC pre-installed with a Linux distro. I wouldn't expect my wife to install any variant of Windows. However, when I've previously bought PCs with Windows pre-installed, I've always had to clear the HD & install again, due to the bloatware & poor configuration done by the PC 'manufacturer'. I don't know if the same applies to Dells pre-installed with Ubuntu.
I don't run servers. My wife uses a desktop with Ubuntu Gutsy and there have been very few problems with it. She also has a laptop with Windows XP (because I haven't got round to putting Ubuntu on it) and there are frequent problems with it. The latest was that it suddenly refused to print to a networked printer. I ended up 'removing' the printer & installing it. The Microsft knowledgebase was of no help.
Often, people make valid criticisms of the documentation in Linux distributions. However, the distribution companies need to make money. As the software is normally free, the usual way to do this is via selling training & manuals. However, people are often unwilling to buy these.
Users often say that a particular Windows application (e.g. Photoshop) is not available in Linux. However, they seem to be unwilling to learn a free of charge application (e.g. GIMP) or criticise it as not having some of the facilities of the Windows application.
Both the above characteristics really stem from many people wanting to have something for nothing without being willing to put in some extra effort themselves. I suspect that this is one of the main reasons why Linux distros will never wrest the mass market from Microsoft.