I got a hold of this week's issue of Business 2.0 and they have a brief section where they reviewed three ergonomic keyboards. On the block were the CKS Comfort, the Kinesis Advantage Pro (the keyboard I've had for the last two years), and the Adesso Tru-Form Media.
The CKS Comfort got 3 out of a possible 4 stars (or maybe 5... it's not clear, and they didn't seem ecstatic about any of the keyboards), the Kinesis 3.5 stars, and the Adesso 4 stars. The blurbs are pretty short, but here's what they said about the Adesso:
"Buy this one if your wrists are basically fine, but you want an inexpensive hassle-free way to keep them that way."
Cons: "The one-size-fits-all layout isn't ideal for those who suffer from extreme wrist discomfort."
Pros: "This standard ergonomic keyboard has split, angled sections and a soft natural curve."