The bottom line, 1 oz of Silver is 1 oz of Silver regardless of the coin you Choose, or what design makes you feel good Dont be tricked in to thinking that a low mintage or high MS coin is Going to bring you more dollars in, in the long run its the premium You have to pay for now that you might not get back later is the Problem.
Yes, the premium you pay and spread between the buy and sell price is what matters. You are correct. But then that contradicts your simplistic folksy wisdom of "silver is silver." You should not buy something that has a poor buyback price and/or is difficult to resell. Not all silver is easily resellable silver. If you don't believe, go see how much you can sell your 40% halves, war nickels, or Queen's Beasts high premium 2 ounce coins for.
Timing is everything. For example, 5 coin 2011 ASE anniversary sets sold for $250 W/ limit of five sets to the same address. Eight years later they still sell for a significant premium. MS70 sets still sell for a very significant premium
Its a long standing argument, but grading bullion 99% of the time Doesnt make allot of sense, why ? because most bullion coins are Of a high MS quality usually 67 plus, so why pay the extra premium I guess there are certain exceptions but for the most part this Holds true.
I intend to head to Canada in the event of an apocalypse - assume the red suited Mounties at the border will be more easily bribed (or sympathetic) with a sack of silver Maples. So I keep a stash for just such an event.