Ron Guth:
Thanks to a large mintage, the 1857 Dime is a common coin in most grades. In fact, apart from the 1853 With Arrows Dime, the 1857 has the largest total population (per the PCGS Pop Report) of any Dime of the 1850's. Mint State examples are plentiful, and there are plenty of MS63's and MS64's to go around. Gems start to become scarce; in MS66 and better grades, the 1857 Dime is very hard to find. The highest level for this date is MS67.
Jerry Fortin has identified fifteen die varieties for this year.