I bought this for rs-650 one year ago . it's still working on the batteries that came with it . i use it very much . I Plugged the Nano Receiver and haven't removed it once from there. On/Off Switch is there which can be operated through the mouse ( though i don't use it ) and Smart Sleep Mode Key Saves Precious Electricity,Logitech Advanced 2.4 GHz Wireless Connectivity that means can be operated from a distance easily. I don't had any problem so far. Dropped it on hard marbel floor quite a few times, but it has continued to work. no problem or malfunctioning even once . Battery life is perfect .
My previous experience with wireless mouse & keyboard was horrible (HP sucks!!!). So I was bit tensed while buying this one. But this little gem of a mouse has been superb so far. Truly value for money. It is an absolute steal in this price. The mouse is very comfortable and comfort is felt by everyone who uses it.
I will definnately recommend you that if you are buying a wireless mouse just go for it, you will never regret your decission.