dude i have this exact mouse and love it to pieces - id be hard pushed to use a different one now.
fits in the hand great, not too "chunky", great range and yeah the batteries do last well.
Unlike a lot of other wireless mice (I've had anyway) it has a power on/off switch underneath. This means the batteries last longer because you can turn it off when you power down your pc.
I use rechargable batteries with mine, these only need replacing every 6 months or so
