When I try to look something up on the web and I can't find it, and I later find the answer myself, I feel like it's my responsibility to put it out there. That's how this got started.
A wider question is why? The short term answer is two-fold: first, I switch back and forth between mouse and trackpad a lot and wanted to see if I could make room for both on the keyboard tray. My preferred keyboard since the mid-90's has been some version of the Microsoft Natural ergonomic keyboard, but the current version is huge (Microsoft Natural Ergonomic Keyboard 4000). And like most keyboards it has that annoying numerpad on the right that just takes up space and makes you reach further for the mouse. If Microsoft sold the same keyboard with the numberpad on the left, or a detached numberpad, I'd probably never buy anything else. But they don't. (I've thought about trying this but I think it would be more difficult with the current version.) This has annoyed me for years, especially the last 8 or so years when carpal tunnel syndrome has occasionally caught up with me, but wanting to use the trackpad is what finally pushed me over the edge and sent me off looking for the best approximation I could find to a smaller footprint ergonomic keyboard.
A bit of background: my previous job had me at a keyboard most of my waking hours -- frequently from 6am until midnight, sometimes more -- remotely overseeing operations of an instrument on a telescope several thousand miles away, jointly operated with some folks several thousand miles away in nearly the opposite direction. We communicated via various chat clients so I'd be typing nearly all that time. And my carpal tunnel syndrome really took off. My employer had various keyboards I could try including the Goldtouch split keyboard and the Kinesis Contoured (but not the Kinesis Freestyle). I didn't really like the Goldtouch although today I can't recall the specifics, and the Kinesis Contoured was a bit too much of a change for me. I preferred the Microsoft keyboard to both. I did change out mice a lot which was a huge help, and maybe I'll get to that in a bit.
My current job is much more mixed, I might be at my desk for a few hours but then I'll be off in a lab working on some hardware. The lack of so much constant repetitive motion has mostly kept the carpal tunnel syndrome from flaring up, it only really happens if I strain my wrist working on something. I point this out simply because ergonomics are a concern but are not currently the driving force they once were in determining my setup -- if they are for you, you should keep that in mind. Having said that, I did something to mess up my right wrist yesterday and it was pretty uncomfortable this morning but has been getting progressively better as I type this post, so it can't be too bad.
Here's the full setup, with the Kinesis Freestyle for Mac, VIP attachment, and to the upper right the separate keypad. (Click on the photo or visit the Flickr page for a larger view.) My initial impressions: the trackpad fits there nicely, but it's lower than the keyboard and a bit awkward to access, I'll probably try to find some way to prop it up. I do find myself at times using the trackpad and mouse simultaneously, trackpad to scroll and mouse to point.
As for the keyboard itself: the wide split feels comfortable but is going to take some getting used to. It forces me to move my hands less (reaching over to the wrong side is just too much of a reach) so that's probably a good thing. I'm also not much of a touch typer, I'm often glancing at the keyboard as I type, but strangely I find myself doing that less with this keyboard even though it's new and unfamiliar. I guess my hands just don't have as much space to get lost. Since it's not a fixed keyboard, if it doesn't feel quite comfortable you can easily shift it around a bit and try a different angle, that's nice but I'm not sure I'll ever stop fussing with it. (Mixing things up may well be a good thing to avoid repetitive stress though.) I miss the larger keys on the Microsoft keyboard, the biggest hitch being the command (Alt on the MS keyboard) key -- for copy, cut and paste I'd hit that with my thumb, that's not very practical now. The forward and back delete keys next to each other have caused some unexpected deleting. I'm not used to the somewhat exiled ESC key position yet, but I'm getting there. If you're coming from an MS Natural keyboard, one nice thing is that (other than the F keys) the keyboard is split in the same place.
In the greater scheme of things the feel of the keystroke is in the same ballpark as the MS keyboard, neither are my favorite ever but I vastly prefer it to the current line of Apple keyboards for instance. Initially I thought these keys felt a little more, I don't know, soft and vague, but after a morning of typing they feel fine and I feel like I'm typing faster than on the MS keyboard, so I think it's just the initial impression from these keys taking a bit less force. A huge bonus to me is having a keyboard with the keys in the right place for OS X and the additional mac keyboard volume etc. keys -- in other words, a Mac keyboard instead of a remapped Windows keyboard. Things will be a bit weird when I boot up in Windows, but Windows is all about confusion, frustration and discomfort, so I doubt I'll notice. (Or, to be fair, it's simply never concerned itself with being the opposite of those, but I'm getting off track.)
You might notice I have a small collection of pointing devices -- as I mentioned briefly before, when my carpal tunnel syndrome was at its worst I found alternating pointing devices was a big help. The least stress-inducing was the Evoluent VerticalMouse 2. You can read my review here, the short version is yes it works to reduce inflammation but that's the only reason I'd use it, and as you can see it's not even on my desk now. My favorite mouse is something like the (ancient) Logitech MX510 -- I really prefer a minimum of 6 buttons and the kind of accuracy those mice give when, for instance, working on a photo in PhotoShop. I can't use the VerticalMouse at all in PhotoShop, maybe the newer versions are better though. The Microsoft Natural Wireless Laser Mouse 6000 (soon MS product names will be full paragraphs complete with specs) is a reasonable compromise, the pointing is a little more sloppy but it's more comfortable, and I alternate between that and the Logitech mouse. If I'm just browsing the web the Apple Magic Touchpad is great, for photo editing it's great to use for scrolling around, and the gestures in OS X make it a pleasure to use in general. But as a precision pointing device, a mouse is better. (And with "Magic" in its name, you might be disappointed to find that its use is not accompanied by singing pixies and dancing unicorns.) Finally there's the Apple Magic Mouse, which seems like it might be a nice compromise between the trackpad and the mouse, but every time I start using it the lack of a middle button kills it for me. (And again, no pixies etc.) I guess I should try this at some point.
So I'll see how this works out and I'll update this post or add additional posts or something. I've put this on my pretty-much-never-used blog instead of my pretty-much-never-updated webpage in case anyone wants to ask any questions.