For the price they are talking, just go with the AR7200BX. It has an AR7200 Spektrum DSMX Rx built into it, and with a 450, you won't need a satellite Rx. And, it's only a little bit more money. I'm running a 7200bx on my helicopters and the thing just works. A little twitchy on a 450, but on a 600, it's solid as a rock. And yes, you can dial it down to make it less twitchy on a 450. It's a great gyro. This is my vote.
Another option is the Ikon. But with an Ikon, you MUST have a computer to set it up on.