I don't have the exact setup your looking to buy, but I have this
one. I am using NiMH rechargeable and in the mouse they last about 3-4weeks, the KB I haven't had to recharge yet (it's been 3months since I bought the KB). My only gripe is the receiver is picky on where you put it. It seems sensitive to interference from the other computer components and can drive you crazy at times unless you move it. Other then that it's a great setup.