I have the Network Extender as well. I got it a while back, probably close to a year ago. At my house I get decent reception outside 3 or so bars, but there are areas inside my house that were a complete deadzone without it. Obviously your miles may vary.
Anyhow, remember there is usually a coupon coupon code for 20% accessories, which I think is always ACC20 not sure about that though. I don't remember why, but I got a $50 mail in rebate as well. So all in all I got it for $150, and now I get great reception in my house. Easily paid for itself in that time.