David Akers (1975/88):
With respect to both popualtion rarity and condition rarity, the 1915 is very similar to both the 1911 and 1914. It is not as rare overall or in gem condition as the 1909 and it is also not nearly as rare in gem condition as the 1913. Most Mint State examples grade in the MS-60 to 62 range, but MS-63 quality specimens are also available from time to time. Above MS-63, the 1915 is not seen very often, and gems are really very rare. A very few examples exist that are better than MS-65, including two that I have seen that could reasonably be graded "Superb," i.e. MS-67.
The 1915 is always very sharply struck. The surfaces usually have a satiny sheen to them and the lustre is invariably excellent. Color is also a strong point of this issue, usually a rich orange or coppery gold. From an overall "eye appeal" standpoint, the 1915 is an easy winner over the other Philadelphia Mint issues from 1908 With Motto to 1915; only the 1912 even comes close.