Logitech V400 For Laptops full review
Unlike the Mighty Mouse, the V400 has a separate 2.4GHz receiver USB dongle, which can be neatly stored inside the rear of the mouse when not in use. This enables the device to work up to 30 feet away (if you ever needed a work radius that large).
Perhaps of more importance is the presence of a Dual Laser Engine. According to Logitech this produces better precision and the ability to work on most surfaces (except reflective surfaces such as mirrors).