I've tried using it for a week. Its not usable. It has a lag in response time when first moving. Its probably an internal battery saver feature. But no way to adjust it falling to sleep mode. The other problem is its very smooth to the point of being slippery. I've corrected that by scratching the surface and then spray-painting it. I'm still searching for a way to force it not to go into sleep mode. The Ergonomic and comfort are both 5 stars. But that is pointless if it can't move smoothly all the time.