David Akers (1975/88):
There are two main varieties of this issue just as there are two varieties of the 1873 Philadelphia Mint issue. Both varieties are scarce but the Open 3 variety is the more rare of the two. As a date (i.e. not considering the two varieties as separate issues), the 1873-S is similar in overall rarity to the 1869-S, 1870-S 1871-S and 1872-S. However, the 1873-S is not as rare in full mint state as the four S-Mints immediately preceeding it. Nevertheless, in strictly uncirculated condition, the 1873-S is scarce and in choice or gem Unc. it is definitely rare.