I really wanted something portable and small with a retractable lead. This mouse does everything advertised. The extendable lead is particularly good (unlike some laptop mice where the retracting mechanism seems to get stuck or give too easily, yanking the mouse away from you).
My one criticism of this mouse, which may lead to me replacing it within about 6 weeks of buying it, is that it is making my hand ache. My PC use hasn't changed, and I've used both full sized and micro (smaller than this!) mice before without that problem. I'm not sure what it is about the mouse that's causing it - perhaps the steep angle of the buttons on the front - as my hand seems very arched. The sides aren't very grippy, and if I try to lay my hand flat I lose the precision I need from the mouse. I'm sure different hands need different mice, but this has been my experience of the product so I will include it here.