Gramma bought a second hand one in NZ for us when we were there, it was a safe and sound brand - kinda ugly, but OMG - fabulous reception! Mum and Dads place is about 75sq, so its a huge house, and the baby monitor was able to go from the top floor all the way down to the shop, and that was through layers of concrete, heaps of wires, and loads of furnishings. I was very surprised. It was easy to just clip on my pants and carry around, and I just left the cord to plug into in the sitting room.
We are currently borrowing a babycoom one, and while it looks cute, it is a heap of crap. I couldn't believe that it was staticky only 5m away from the baby unit.
Would not recommend it.....
Fi