Both are amazing optics and will serve you well. Pick based on the reticle, unless one has another feature over the other that you want/need (for instance, the AMG is almost 20oz lighter, but the Razor G2 has a 34mm tube and a 56mm objective as opposed to the 30mm and 50mm of the AMG).
Me? I'd go AMG. I prefer the reticle, don't need the rev indicator of the G2, and the AMG offers plenty of elevation at over a pound in weight savings. I'd be tempted to go with a Gen2 if I found one at an amazing price, though. At how heavy my AIAT is, I wouldn't notice the extra 20oz.
I have both scopes either will suit you well. The AMG is lighter, has the ability to lock the diopter in place but does not have the little indicator to tell you when you are above 10 mils.
The Razor has more magnification, does have the revolution indicator, and has a 56mm objective which gives you a better field of view.
I own 3 Razors and one AMG and both are great scopes.
For the PRS game either will work just fine. The differences have been noted already. The weight difference and reticle are the two things I would use to make your decision. If you wanted to have it lighter than the AMG.
The mag range is almost identical and the small differences on top and bottom won't matter in the sport as both have plenty on the top end and you will probably never go below 8x anyways. With the zero stop the turn indicator is nice but not a must have as you can always dial down to the stop to find your bottom. Also in the sport you spend most of the time in the first turn with most calibers.
I own and have used both in matches and both work excellent. No wrong answer.
I think the Razor has a bit better FOV and stupid good eyebox (important for awkward positional shooting in PRS). Also, I like my guns as heavy as possible to make them more stable and balanced on a bag. Also, they are less affected by free recoil. Others have listed some other differences.
For STRICTLY PRS I think the Razor II is the better scope. For almost any other application, the AMG would be a better choice due to weight.
I use both...on the same and different rifles. the matches I've shot not much "hiking" was required so never noticed the weight difference.
I like AMG's reticle better.
I like HDII's eyebox better.
I shot better with the AMG though haha....