The page-up/down keys are unusually placed, but anyone who spends time with the board will get muscular memory going in a short time. I hit those keys without looking any time I choose. It took a day to master without misses.

This keyboard is better than any other I have ever used - full sized, compact, corded or cordless, adb or USB, - I've used them all. This one has the wrap-around key layout that keeps my wrists straight, and a wrist rest that absolutely prevents forearm fatigue I usually get after an hour or so of keyboarding. The key action is wonderful, providing the resilient resistance that makes touch-typing easy and error-less.

The mouse was a wash; it's in the trash, but I didn't buy a mouse; I bought a keyboard. I still use my Kensington wireless, which has superior tracking and accelleration. It's been over a month on the original batteries that came with with the keyboard, two AA's, which makes it dirt cheap to keep in power. Battery consumption is low. The board is a little narrower than some other ergonomic boards, which means it will fit on my lap regardless of which chair I use, wide or narrow.

All in all, this is one of the better purchases I've ever made, and I recommend this keyboard to anyone with high expectations for computer hardware. This is a professional level board, possibly the best there is.

The Comfort Duo on the other hand is *outstanding* with one small exception. The keyboard feel is very nice, with good but not obtrusive tactile feedback, good key placement, a nice wrist-rest and it looks nice as well. The mouse is superb, although the buttons seem a little closer together than I'm used to with other mice (I keep missing the right mouse button hitting the mouse housing instead) but I'm sure I'll get used to it.

The only disappointment (and this is a big one, I'm afraid - the reason I didn't give this set five stars) is the placement of the Insert/Home/PgUp/Delete/End/PgDn keys. Instead of placing them in the "standard" layout of two rows of three keys each, ordered as I typed them above (heck, even my laptop uses that layout!), Logitech has opted for a screwy three-row layout that places the "Delete" key right where your hand expects the "Home" key.

It's bad enough that touch-typists like me had to adjust to placement of the "6" key on the wrong hand when they started making these "ergo" keyboards, but it's a shame that Logitech had to go and spoil an otherwise perfect keyboard for no reason that I can tell, other than allowing them to shorten the keyboard by a half-inch....

Here are the problems:

Keyboard:
1. The strangely laid out home/end/pg up/pg down/insert/delete keys that everyone has mentioned.
2. In order to conserve space, the different key pads are placed uncomfortably close together. The letter keys, the home/end/cursor keys and the numeric keypad are so close together that they are almost one continuous keypad. This makes it difficult, tactily, to move from one set of keys to another. This sort of defeats my purpose, which was to buy a full-sized keyboard for my laptop. For instance, when I use the page up/down keys, I have to be careful not to press on the numeric keys. These are not things I need to be thinking about when I am touch-typing.
3. Again, a space-saver issue. They have brought the function keys right down on top of the letter keypad and the scroll-lock/print scr/pause keys down right on top of the numeric keypad. I use the numeric keypad a lot and because they have basically added a 6th row of keys at the top, my hand is always positioned on the wrong keys and I'm typing all the wrong characters. Same with the function keys, which I also use a lot. Not only are they right on top of the number keys of the keyboard, they have these sort of random spaces between them, which again, makes them very difficult to use when touch-typing. With this keyboard, I've been forced to resort to hunt-and-peck typing a lot.
4. One last negative. Yet again, a space saver issue. The right shift key has been reduced to nearly a "normal" letter-key size in order to squish the cursor keys right up against the letter keyboard. This makes the "enter" key stick way out past the shift key. And again, tactily, I constantly end up pressing Enter instead of Shift because the shift is a good 3/4 inches in from the end of the Enter key.

Mouse:
1. Huge mouse. Not good for small hands, which I have. It is also a right-handed only mouse. So if you're a lefty, you're out of luck. I'm not a lefty but I mostly use my left hand for the mouse and I switch to my right, when my hand get's tired. It is nice to have that versatility.

I suppose once you get used to these inconsistencies, it would be an adequate keyboard. But I wonder why I should have to relearn to type to suit Logitech's quirks? P>The one thing that the old MS Natural keyboard and that none of these new split keyboards have is the reversed "stand" (can't think of a better word) where it tilts the keyboard AWAY from you rather than toward you like they all do now. When the keyboard is tilted away, it is much much much more comfortable. I have seen other people mention this as well. I wonder why they did away with that excellent feature. Right now I've propped up the Logitech with a piece of wood under the wrist pad. Makes a world of difference.