I used to have one of those LRP dischargers years ago, but they're not that useful IMO. They have no voltage cutoff built-in that I could tell, so it's really guesswork as to how long you should leave a pack on it for (just has an LED which gets dimmer). It might be useful for the absolute beginner who wants to discharge a pack to avoid it sitting charged for too long - if their RC has broken down or whatever - but other than that, it's not going to be very helpful I'm afraid.
You're better off sticking to the discharger that's on your Prodigy; you can at least set a cutoff voltage on that.