Among later-date Barber Half Dollars, the 1908-S is a real standout. According to the PCGS Population Report, it has the lowest overall population of any date since 1905. The same is true of the Mint State populations, which are all very low relative to the surrounding dates. Gems are rare but, fortunately, there is a handful of examples at the MS65 and MS66 levels. MS67 examples are exceedingly rare. As illustrated above, most of the top-quality examples are toned to some degree, usually in impressive arrays of different colors, and their eye appeal is overwhelmingly positive.
The strike quality on 1908-S Half Dollars is usually good with these occasional exceptions: 1) softness on the upper-right corner of the shield and the adjacent feathers and 2) roller-marks (actually draw marks) which were not crushed out completely when the coins were struck. Unless obvious or distracting, either of these conditions should affect the value to only a small degree.