We have one. We set it up in our room since that's where DD's bassinet is, and got it up and running a few weeks before she arrived to test it out. You know, for quality assurance.
I'm not sure if it's made a difference for her or not, since she's slept with it since we came home, but it's definitely helped me out, and I plan on getting one for us once we move LO to her own room.