Ron Guth: In 1867, the Mint continued using a reverse with the rays interspersed between the stars. Problems in striking the coins continued, particularly the difficulties in bringing up all the details and with dies cracking prematurely. A decision was made to remove the rays, in the hopes that their removal might solve some of the production problems.
The mintage of the 1867 With Rays Nickel is a fraction of that of the 1867 No Rays, but the difference is not so stark in the number of certified examples. For instance, the PCGS Population Report (as of June 2011), shows 547 With Rays and only 800 of the No Rays. Perhaps collector interest in the No Rays version was not great enough to preserve large quantities of the newer version.
Mint State version are relatively common and are most likely to be found at the MS-64 level. Gems are scarcer and the finest example graded by PCGS is a single MS-67.