I reviewed the Microsoft Natural Wireless Laser Mouse 6000 a month ago, and gave it a 'close but no cigar' verdict. It went most of the way to offering a handshake use position, but stopped short when compared to mice like the Evoluent VerticalMouse. After another four weeks of daily usage, I'd like to revisit the review and now say that this 'close' verdict should, for me, now be moved to an 'ouch'.
I have big, but not gargantuan, hands, so this could be a factor, but after more and more use I found my wrist was starting to tell me it wasn't happy with how things were going. A shift back to my standard Wireless Laser Mouse 6000 and my wrist relaxed a little more. That just shouldn't be the case - a 'natural' ergonomic device should be comfortable and intuitive, and no matter how I have tried to adjust the way I position my hand I just couldn't get it into the right position.
Let me note here I'm more of an ergo-nut than your average user. I'm sitting on a Herman Miller Aeron while working at a height-adjustable desk (review later this week) so I'm not pouring all my ergo hopes into one little mouse - so my experience can't be discounted as a result of my general bad posture / position at my desk.
I have just recently noticed the mouse was making my wrist work in a more flexed position than a standard mouse, and this seems to be where the pain was coming from. In my opinion, by not going to a full handshake position, Microsoft have given us a mouse that feels tall rather than twisted on its side and this is where my hand and wrist has been troubled.
So I'm firming up my concern over the not-quite-handshake orientation. If I can have a more comfortable experience with Microsoft's standard mouse designs, then this Natural mouse feels like a failure. Microsoft should either release size options to suit small, average and large hands, or they should go all the way and release an ergonomic mouse that goes completely sideways so we can mouse in total comfort.
Now I'm off to buy a trackball.