It depends on what you would consider "hard." I tinkered around only a tad bit in Linux, and always thought "Hmm... that's interesting. But it looks like crap (or it doesn't even work), so I'll go back to Windows." The first *NIX I actually used on a regular basis was FreeBSD. Around that same time I started to use Linux a bit more, and today it's strictly FreeBSD. There are a few Linux distros that I'll always like and have a general respect for, but I honestly can't see myself using anything but FreeBSD (well that and Mac OS X on my laptop). And of course Windows at work
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