Angelcare all the way!! We've had two false alarms when Ross had managed to get right up to the top of the bed when he was much smaller, but it turned out I had shifted the sensor pad when I had changed his bed. My concern isn't the crying, cause you hear when they're awake, it's the silence! Especially when they are on their tummies it can be hard to see them breathing, and I assume if a LO was to stop breathing they wouldn't do it 'loudly' to set off a normal monitor. So sorry, not trying to freak anyone out! Just trying to say that you don't have to watch the monitor for lights or whatever when you know the alarm will ring out if there was a problem. Your mind soon settles into that idea, and of course like Emmamb said you get a big reminder if you forget to switch it off before lifting bubs.
Tiny that is a good price, think we paid £60 when it was on offer, but I've seen it more recently in Tesco for £50. Hunt around. I definately would not be without ours!!