Being a basic laser mouse, the MX400 isn't much to look at, and for the most part, this isn't a bad thing. Unless you're a gamer (and absolutely demand that everyone knows it), you probably don't want your mouse to be the centerpiece of your office. The contoured gray and black plastic of the Logitech MX400 give the impression of a quality product, although the visible lack of buttons also makes it clear that this is not luxury hardware. Personally, I like this basic, no-frills look far better than the strange patterns that seem to cover Logitech's gamer-oriented laser products.
Touch the MX400, however, and you'll wish you hadn't. The MX400 may look solid, but it feels flimsy. Largely because it is incredibly light. Bundle up a sheet of construction paper, hold it in the palm of your hand, and you'll have a good idea of how light the MX400 is. I found this to be a downer. The total lack of weight made the MX400 easy to knock about accidentally, as the slightest fidget will translate into on-screen movement.
I also had problems with the size of the MX400. Although not as gigantic as Microsoft's pudgy "Natural Mouse" series, the MX400 is no little squirt. It easily dwarfs any of the older mice in my stable. Although the contours of the MX400 give the impression of a mouse designed to work with the natural pose of the human hand, I found that my own digits were not comfortable. My main problem is that the mid-section of the mouse is tall, causing my index finger to curve significantly. This resulted in cramping after an hour of use. The MX400 is fairly comfortable to look at, but to use? Let's just say I wouldn't wish it upon a friend.
