It's a bit like ice cream flavours, it's the upside and downside of Linux in general. There are so many distros it comes down to personal taste. Plus, 'power user' is a very subjective term. A real power user just wants a command line, but I'm guessing that's not the goal. http://distrowatch.com/dwres.php?resource=major
That's still a pretty good reference site to get caught up on the latest distros. I personally still prefer opensuse, but I don't 'push' distros anymore. It's like saying I like my potatoes mashed, not fried. Just plain crappy or buggy releases are worth avoiding, of course, which is why I still like that website.