I have to agree with most of these postings having owned 4 different Martins over the past 20 years. I never bought a new one, and never lost a dime on any when selling them.(made good profits) I did come to a point when I realized that there is no such thing as a guitar that can't be replaced. Each Martin had it's own voicing and my first Martin was a 018 and barked like a junkyard dog.(terrible sound) My last one was a heavy handed S35. There isn't one that I thought I had to keep forever or pass on to my offspring. Another phobia I put behind me was always looking around to eye watch my valuable "Martins". Now if I loose my main ax, I feel I can replace it with a hand built that is even better than the last.
My main guitar today is a fancy T Harua mod 150(Japan 78) with a whole ocean of abalone inlays. I have kept this one the logest of any, and more times than not, Martin D45 owners think it's a Martin. It's a better than most copies of a D45. I'm wearing down the second set of frets and will likely have to have the neck shaved down to renew the action as it has experienced some abuse from flight attendants.
Martins are a better investment than they are "great guitars". My humble opinion.
Mudjack