The 1864-S half dime is PCGS AU-53 CAC with a mintage of 90,000 and the 1875 20 cent piece is PCGS AU-55 with a mintage of 37,000. I could use both for my Liberty Seated type set but will have the funds to purchase just one of the two.
To be honest, I like neither. The 20c has unattractive hairlines to the left of the portrait, and some type of tarnish/residue on the reverse.
I prefer the color and character of the half dime. Do you have a larger image of it? The twenty-cent piece seems a bit flat, but maybe that's just the pic. But I don't care for the discoloration on the eagle's wing.
Because of those atrocious scans on the dime, I'm going with the 20c piece. It's always hard to gauge what a coin's true color will look like from scans, however, I imagine that that coin will be just as rustic looking as the scans depict. That might be good, if you're into that kinda thing.
I think I'd choose the double dime. P mints are hard enough to find, but one with original surfaces is really tough. (nothing wrong with the half dime though).
I love double dimes, they are my favorite denomination when it comes to u.s. coinage but as mentioned the hairlines on the obverse field and the black tone streak through the eagles right wing turn me off. Go for the half dime. Nice & historical date.
