We have it, and have the second camera set up, but obviously aren't using it religiously just yet.
It's very easy to switch - it's one button that let's you switch, or you have the option to set it to scan back and forth between the camera every 12 seconds or so.
I also love that the screen doesn't light up at the slightest sound. Just the sound monitor lights up, and then you can turn the screen on to see what the noise is. Much better for a good night's sleep when baby is just cooing and rolling over into a different position.