I tried this with a generation 1 iPad and the 2013 Keynote. It was easy to set up and get running. However, it only displayed the current slide with just a background for the next slide and empty presenter notes. Perhaps the Pro version would fix this. But it seemed to be very slow with updates. This meant that time was needed before advancing again. Because of this slowness, I elected to not try the Pro upgrade.
jfschultz about Slideshow Remote® Lite