I've been using Python since 1.5, and I've always considered it my secret weapon to get things done faster than anyone thought it could be done. All while producing code that is easy to read and maintain, unlike the popular scripting disaster at the time that was called Perl. Over the years its usefulness has only expanded to areas I would have never expected. And so it remains as my not so secret weapon to this day. Is it perfect, no, no language is. Like all languages it has its place where it works well, and plenty where its a bad choice.
Most griping in this thread are by people that clearly have not used Python for anything significant, but have heard about the GIL issue, and feel they must whine that their favorite language is not more popular. The GIL issue can be dealt with in a number of ways, Jython being my favorite. The GIL has never been an issue in anything I've done with Python, for two reasons. One I've never used Python where that would be an issue, and two when I have chosen Python, I designed code so it would not pose a problem. It's a bit crazy, but this seems to work.