Unix is cryptic
The truth of the matter is that Windows NT Server is just as administrator-intensive as UNIX and, according to people who've used its smiley-face GUI, you still have to get down into the command-line level to actually administer it. Just like UNIX. How unusual... "Those who do not understant UNIX are destined to reinvent it, poorly." -- Henry Spencer and Geoff Collyer.
Unix is not user-friendly
A famous wag once said "I don't want user-friendly; I'm not a friendly user!". So-called user-friendly systems are really novice-friendly. Easy to use for novices, but often limiting once you move beyond that. And most users who put in time don't remain novices all that long.
Unix does not adhere to standards
Hello! The POSIX standard is based on the UniForum standard, based on the /usr/group standard, that I worked on in 1983 (yes). All modern UNIXes adhere to POSIX. Windows NT just barely does, and only fully if you add on commercial third-party software.
Unix does not have a standard GUI
In fact, it has three or four: So the claim "doesn't have a standard GUI" is true, from a certain point of view. But it's misleading.

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