I love your sig line, averyb2. Nothing like honesty to strike up a conversation. 
The decision to be made between your two coins also has to involve conditional rarity and demand, if I read correctly that your desire is to buy the coin which will tend to gain value better in the future.
My point is, the low-MS common coin might not be so common in that low MS grade. For example, there are a bazillion 1884-S Morgans, but if you want one in MS, you're gonna pay because they get pretty rare in that atmosphere. Or, it might be subject to much greater demand because of popularity than the higher-grade coin. I might make that distinction between an MS65 Morgan and an MS65 Three Cent Nickel, just because there are so many more collectors interested in the Morgan.
Hopefully you're more befuddled now.
If it were me, I'd always go for whichever coin was rarer in the grade. Unless, of course, the other one was prettier.
The decision to be made between your two coins also has to involve conditional rarity and demand, if I read correctly that your desire is to buy the coin which will tend to gain value better in the future.
My point is, the low-MS common coin might not be so common in that low MS grade. For example, there are a bazillion 1884-S Morgans, but if you want one in MS, you're gonna pay because they get pretty rare in that atmosphere. Or, it might be subject to much greater demand because of popularity than the higher-grade coin. I might make that distinction between an MS65 Morgan and an MS65 Three Cent Nickel, just because there are so many more collectors interested in the Morgan.
Hopefully you're more befuddled now.
If it were me, I'd always go for whichever coin was rarer in the grade. Unless, of course, the other one was prettier.



















