"Here is my opinion speaking in generalities:
General information:
Between 1966 and 1988 Martin used Rosewood bridge plates which were inferior to the Maple bridge plates used before and after. I would not buy a Martin guitar unseen from that period and likely not at all."



As a reference point to the posted statement; this is not always true.
Martin began production of the HD-28 in 1976 and it cured two of the biggest ills of Martin in this time period. The HD-28 has always had a Maple bridge plate in place since its beginning along with the scalloped bracing. Two things that Martins in the seventies had and have had their opponents say. The only things missing from the older HD-28s and could be considered "undesirable to some" is the T-bar truss rod. I have in fact played a few HD-28s from the 1976-79 period and they are one of the most resonant guitars I have had the priveledge to play.

Don't discount Martins from the seventies, besides the intonation issues that some could have in the earlier part of the decade which are easily set right; they can be great aged tone wood guitars at a great value. Just to keep things in perspective; Martins in the seventies are no where near what Fender and Gibson's woes were in the seventies and they are now beginning to see vintage status.