Having worked at both, I can assure you that ThoughtWorks are thought leaders in the agiile development and change. It's hard to get in and you have to be talented to stary there.
Accenture on the other hand, they make it hard to get into the consulting arm, but the tech arm (Accenture Solutions) is easy to get into (although you'd be surprised at how maby people tank in the interviews) and even easier to coast through, producing crappy software and bleeding their clients dry.
Having worked at both, I can assure you that ThoughtWorks are thought leaders in the agiile development and change.
Trying to convey the perception of "thought leader" (which is really a horrible term), and how they are perceived by the software development community are two vastly different things.
I have experience with ThoughtWorks, they turned a mildly complicated problem into a massive architectural wonder of the world, perhaps practicing their design patterns.
I witnessed a similar project unfold. Eventually, I believe, most of them were kicked off the project and it was brought back under control of the company I was working for.
