Will it still leap from one side of the screen to the other at the whim of the mouse driver because of some dirt or "thing" on the desk that interfers with the beam.

Still 50 quid for a mini mouse is a little steep.

That seems to be the biggest limitation of most optical/laser mice, although I've never tried carpet or asphalt.

I guess it just goes to show that even Satan incarnate can do good things.