The one thing that we can say Microsoft has been consistently good at over the years is their keyboards and mice. The new set of mic use Microsoft’s "BlueTrack" Technology. The light is now a blue hue which Microsoft claims that it can better pickup the frequency of blue light and by using this, you can use the mouse on almost any surface all while maintaining the accuracy of current laser mice. The advantage of course is that the blue light is an LED which allows for longer battery light and extended life.
There are currently only 2 models using this technology, the Explorer Mouse and the Explorer Mini Mouse. No mention of price yet as they are currently only at best buy.