Ron Guth: The 1880-S VAM 10 Silver Dollar is a Top 100 variety and is believed to be the toughest of the 1880-S overdate varieties. The key attribution point is the second 8, which shows a clear crossbar from an underlying 7. To clinch the attribution, look for doubling on the base of the 1 and doubling on the inisde of the first 8 at the top of the lower loop. The reverse on VAM 10 has a large S.
PCGS has certified over 100 Mint State examples of this variety (as of April 2011), mostly in the MS-63 and MS-64 grades. None have been certified above MS-66 by PCGS. Prooflike and Deep Mirror Prooflike examples exist but they are exceedingly rare.