Hey Will, I own and enjoy shooting two 7.62 ar's. Some benefits are that they use many small parts from the ar15 rifles, the SR-25 mags are plentiful, be it DPMS, Magpul pmags, and even the c product mags. There are many manufacturers jumping into the large platform ar's, and parts and accessories are becoming more readily available… (as much as possible with the current supplies for all fun things being low!)
The Scar H, is also recognized as a great gun, with it's biggest drawback being proprietary mags. There is a company making a lower that accepts the SR-25 mags solving the problem, but another investment is required. Here's the link..
http://www.rainierarms.com/?page=sho...roduct_id=3217
If you have some more questions on the large platform ar's, feel free to pm me, I do have some good first hand info with at least six of the manufacturer's