Silly things like: "On the other end of the spectrum, Gentoo, Debian, Slackware and FreeBSD are more advanced distributions that require plenty of learning before they can be used effectively."
http://distrowatch.com/dwres.php?resource=major
It can be a little difficult if you don't take the time to understand how it works and read the docs. But no more than any other distro. I think the reason some people say it is hard is the "lack" of GUI config tools.
""GNU/Linux is hard to configure."
Note that this says configure, not install, as some people find the initial installation of Debian easier than Windows. A lot of hardware (printers for example) could be made easier to set up, though. Also, some software could have a script that would walk the user through the configuration (at least for the most common setups). This is an area that is being worked on."
The above is from
"Reasons to Choose Debian"
Personally I found it to be one of the simpler distros to accomplish anything with. Plus I was able to install it on my laptop and desktop with no problems.
