The trackball thumb module is a great idea - being able to mouse without moving my right hand off the keyboard would be ideal (you can buy an actual mouse to use for FPS games if you want that). For anyone who is seeing this and thinking they need to upgrade though, know that you really don't have to spend $300 to get a good-quality ergonomic keyboard. The Goldtouch GTN-0099 can be found in like-new condition for $60 on ebay. The Kinesis Freestyle2 is around $100-130. Neither of these have mechanical keyswitches, but I've had a mechanical keyboard before and can tell you the tactile novelty wears off within a couple of weeks. High-quality non-mechanical keyswitches are just dandy these days. So do question whether you really need to plunk down $200 extra for mechanical.
Separately, if you care about ergonomics enough to be interested in your keyboard, don't neglect your mouse - usually a much worse culprit for wrist issues. I recently switched from a vertical-style ergonomic mouse to a trackball and it's enough of a difference to make me a zealot! I bought the Kensington vertical model with a thumb trackball. My small remaining wrist issues are no more.
Separately, if you care about ergonomics enough to be interested in your keyboard, don't neglect your mouse - usually a much worse culprit for wrist issues. I recently switched from a vertical-style ergonomic mouse to a trackball and it's enough of a difference to make me a zealot! I bought the Kensington vertical model with a thumb trackball. My small remaining wrist issues are no more.