For what it's worth, I purchased in round 2 and round 4. Between my experience and that of several friends, it looks like Service Grade is a high probability of getting a govt. contract replacement slide and barrel. Field grade is high probability of an original slide (maybe mismatched), faded finish consistent with usual field grade standers, and govt. contract replacement barrel. As such, if ever I were to go again, field grade would give the biggest bang for the buck. Worst case of severe finish loss a good re-park job is no real loss of value, and likely bumps it up given almost all of these were arsenal refinished at some point.