The 1892-O Barber Quarter Dollar is in the middle of the pack in terms of mintage and overall rarity, and is in the lower half in terms of rarity in Mint State. This means that collectors should be able to obtain a high-grade example of this date with relative ease.
Most Mint State 1892-O Barber Quarters cluster around the MS-62 to MS-64 grades, with MS-63 being the most common by a slight edge. MS-65 examples are scarce, but available. MS-66 and better examples are very rare, dropping to a mere three examples graded by PCGS in MS-67. The overall strike is good for a New Orleans Mint product, but still short of the well-made Philadelphia Mint issues.
Some collectors pay attention to the placement of the mintmark on the back of Barber Quarters, partly out of interest, and partly as an aid in authentication. In 1892, mint engravers placed the mintmark over the R of QUARTER, unlike the placement on all subsequent years, when the mintmark appears over either the D of DOLLAR or between the R and D (the same is true for the 1892-S Quarter). Why the change was made is unclear, as the placement on the 1892-O and 1892-S Quarters centers the mintmark perfectly beneath the eagle's tail.