I highly recommend. I bought this because my wife, having our first child, was obsessed with watching the video monitor all night - thus making her very tired all the time. When I read about this on a daddy blog I figured it was worth the money if my wife could get a decent nights sleep. It worked! After a few nights she was able to not worry as much because we would hear the alarm if there was any issues.
Our baby never had any problems, thank goodness, but we could tell it was working. If you forgot to turn off the monitor in 20 seconds the alarm would go off. Also, we went through adjusting the sensitivity and adding a hard surface under the bed for the sensor to rest on to make it more accurate. There were false alarms at first, but if you get those out of the way in the first couple days you can sleep better at night because of this product.