Just got the MX 700 and cordless Elite Keyboard (Mx Duo) amazing piece of kit! I wish I had bought them much earlier. I too was skeptical about lag, rechargable batteries etc etc. Looks like I was totally wrong in my assumptions. The best thing about the mouse is the rapid charger which is really rapid, I ran out of energy in the batteries and by just putting it into the cradle for few minutes I was able to complete the job at hand. I read somewhere that just one minute charge will last about ten minutes, if that is you run out of power. Overnight charge works for hours in a day which is what I need.