We bought this unit about a year ago and it helped.  We live way out in the sticks and are probably 3-5 miles (as the crow flies) from the cell tower.  Before setting up the booster we were lucky to get any service in the house.  Afterwards we could get 2 or 3 bars, but had to stay fairly close to the base unit.  Recently I added the dual-band directional antenna and our signal strength on both of our iPhone4's is maxed out at 5 bars throughout most of the house.  This product is worth the money as long as you remember to also purchase the directional antenna if you are in a far fringe area.  Adding the external antenna seems to increase the range of the base unit.