How Effective are Ergonomic Keyboards?

Jodrell writes: "This article on the BBC's website has a brief review of the current state of keyboard technology, but also questions the validity of claims that ergonomic keyboards can help prevent RSI, CTS and other "upper limb disorders." The article suggests that maybe it's working habits that cause these problems, and not the design of computer interfaces. What are Slashdot readers' experiences?"