TimDgsr is correct.
THe MS Bluetooth mouse does eat through my batteries pretty fast, but the keyboard lasts for months. But to go around this problem, i bought 4 NiMH rechargable batteries and so this way, when one set dies, i have another to replace it right away, and then i just set the first pair to recharge. These batteries, for me atleast, are worth the cost. They last a lot longer then alkaline batteries and can be recharged!!. So, if you want to get the Bluetooth from Logitech, dont let the battery issue scare you away.
and for connection problems, i havent had any which werent solved by reading the manual. So i can say that connectino is better off then what i used to get with a MS wireless mouse.
raven