For me, I have done the side by side taste taste and prefer the throwback. Some other people have done my taste test and most like the throwback better. Also like the Dr. Pepper Heritage.
Perosnally I would stick to U.S. coins. IMHO, They are easier to recognize by people who do not collect a lot of silver. So if you need to do some trading people may be more willing to trade for coins than silver rounds.
I also think you should go to coinflation.com and use the silver...
I can't remeber which magazine did it , but the author took a variety of AR-15s and abused them to see which ones held out. It was either this month or last month.
I have an 870 with a wood stock that has a slug barrel. It is a magnum so I can use either 2 3/4 or 3 inch loads. I have seen similar ones to mine at gun shows for around $250.