Also, Look here:
http://airsoftsmith.com/store/All they sell is Pantac. They have just about everything RedWolf has Pantac wise. If they don't have it, You can contact them and they will most likey order it for you. Orders over $125 ship free (You'll probably hit that or more getting the RRV and back plate).
I personally like the RRV because it's open in the back, The shoulder straps are a bit wider so the weight is distributed across the whole shoulder instead of a small part (Less pain), you can buy multiple back attachments, you can wear a backpack and it won't get in the way, and there are many other things.
Here are some videos showing different ways to wear it and a review:
Review
Different ways of wearing it
It's an Eagle RRV but you can wear it the same way
RRV and Hydration Back