The U.S. Mint at Philadelphia produced no Shield Nickels for circulation in 1877 and 1878. In 1879, production resumed, but only in limited amounts (this was true of every denomination except for the Cent and the Morgan Dollar). In fact, the 1879 Shield Nickel has the second lowest mintage in it series, second only to the 1880. As a result, there is a lot of collector demand for this date, and prices for higher-grade pieces reflect this demand.
Numerous Gem examples have survived, perhaps more so than some other dates. Looking at the PCGS Population Report, one sees that the most common grade for this date is MS-65, followed by MS-64, then MS-66 (where PCGS cites 22 examples). No MS-67 or better examples have been certified by PCGS.
This date features luster ranging from frosty to prooflike. Virtually all examples show good strike details and the die-cracking that plagued earlier issues seems to be much of a non-issue here.