This Fit-U mouse from Spanish peripheral designer Rainbow has a neat idea. Its top is a detachable plate, allowing you to switch back from a desktop-sized mouse and a travel-sized mouse easily. Too bad the mouse is so bad.
The Price: TBD
The Verdict: Bad mouse, but great idea. The concept of being able to take a regular-sized mouse (the Large plate, in their terms), swapping on another cover and turning it into a travel-sized mouse is a neat idea. Some days you want a large, ergonomic mouse like Logitech's, but some days you want a smaller one to shove into your bag.
The downside is how bad this mouse is at mousing. I placed it on two different mousepads and a desk, and it was never able to track half as well as the Logitech Performance MX mouse. Chunks and stutters were common, and most of the time I was fighting it like an old man new to computing in order for it to do what I wanted. The button presses were hard and clacky instead of being smooth and easy. Overall, bad times.
On the other hand, the top plate is easy to pop off and easy to swap, which is a plus. Its only plus. You have to ask yourself what kind of bag you have that can fit a travel-sized mouse but not a slightly bigger mouse, and what kind of mousing surface really demands a compact device, and that extra two inches just won't do. My feeling is that it's really rare.
So it if weren't for the fact that this mouse doesn't function very well as a mouse, it'd be a great mouse. But in the meantime, you should go with a Microsoft or a Logitech or a Razor; one of the people that have perfected mice sensors. [Fit-U]
Interesting idea for a customisable mouse
Large size plate not that comfortable for a desktop mouse
Travel size plate is about the same as other travel mice
Bad at mousing