Others say...

"Great Ergo Design"
I love this keyboard because of the way, and the angle at which the keys are split. It is perfect for my tendonitis-prone left wrist, which is why I needed it. I only wish there was a bluetooth version because I use it with my laptop and I hate wires!

"Space bar"
I received the keyboard today. The space bar is a big problem. It gets stuck in the pressed position. it is also difficult to press it from sides. you need to push it in the middle which is totally contradictory with the ergonomic design. the design itself is quite good but the space bar, which is maybe the most commonly used key, creates a big problem. I do not recommend this keyboard to anyone. Go for the Microsoft Curve Comfort.

"Heaven"
This is the best keyboard out there and the price is right! Easy to manipulate and works well with your hands. Has a rest and on an incline to position your hands properly. I also use a pad for my elbows. Would recommend highly!

"If there's one thing Microsoft can do, it's gotta be making keyboards."
Because I bought a store model desktop for the family, the store threw in this keyboard for free. I was a little hesitant at first because I wasn't sure if I could get used to the whole "curved" keyboard thing. After using it for about a month, I just couldn't go back to the regular keyboard on my laptop's docking station. My hands feel so comfortable and relaxed using this keyboard, it doesn't even feel like I'm typing!

In all honesty, it only took me a couple of hours to get used to the curved shape of the keyboard. All of these keys are virtually silent (except the space bar, it's noticeably louder than the rest of the keys). Because I use Excel, I'm always using the number pad. If you also use Excel quite frequently, you'll appreciate the extra row of keys over the number pad (has an =, (, ), and backspace).

Overall, I've been using this keyboard for about a month of consistent use. I'm extremely happy that I bought this keyboard and I think it'll last me for quite some time. Whereas I used to hate having to use those "funky" ergonomic keyboards, I now dread using regular keyboards. Kudos to Microsoft for making an AWESOME keyboard.

"Opinion of a gamer"
Biased opinion starts Now:
As a gamer, I needed an upgrade from the regular Dell keyboard I had been using for a few years. I was hesitant on buying this keyboard after reading many many Amazon reviews. Apparently people had a problem with the space bar being stiff. MY spacebar works fine, it just feels like a big version of the other keys so +1 to soft, quiet working spacebar. The other keys are not loud as well so this is a plus. Pressing them is softer than most and can be compared with the Saitek Eclipse II and can even outmatch it in terms of ergonomics. Also, I do not type for a living. I mostly chat with a mic. The reason I bought this keyboard is because I saw it at Best Buy and after resting my hands on it, I felt at ease. It is the most comfortable keyboard I have ever encountered.
A couple of my gamer friends recommended some gaming keyboards and I tried them, but they did not leave an impression or desire as this one did at Best Buy. Among the recommended keyboards are the super popular Saitek Eclipse II, and F4t4lity, both which I believe are inferior in terms of typing, comfort, and gaming. Multiplayer FPS games are getting very popular and the WASD keys used for moving are Very important, and with comfortability comes ease of use.
Try it at Best Buy if you are not sure. Amazon has a good price and eBay does as well of course.
The keyboard works EVEN WITHOUT INSTALLING THE SOFTWARE(I'm using XP Pro), I am typing this entire passage without inserting the CD once. The CD is used for the programmable favorites keys at the top as well as the alternative keys for the F(function) keys and maybe some other functions that don't matter to me. Out of the box, the Homepage key works, the volume keys work, the calculator key works as well as the standard keys. Do not install the software if you do not need it, I definitely do not.
I do not have my fingers on the 8 home keys as pro typers do, I just use what fingers I am used to. You can get used to the split in less than a week. Since I do not type too much, I also do not have to get re-used to regular keyboards at my school either.
This keyboard is the best I've seen even for casual typers.
Either try it or buy it now, Trust me.