"I think the fact that a lot of people feel driven to take their time to write about a tool is much more indicative that it is an incredibly helpful tool, not that it is difficult to use. If you used some tool and it was really hard and barely got the job done, would you feel passionate enough to write a post or tutorial on it? Does horrible usability drive passionate proselytizing? No."

But there are things about git that are non-obvious, and tricky if you've been accustomed to cvs, svn, or even hg.

It's sort of like learning OOP after years of BASIC. Once you get going, you may wonder what was so hard about it, but getting a proper mindset can be difficult.