I've read most of the postings about Martin guitars and the one by Frank Hamilton explains it the best that I've heard.
I'm 72 and have played guitar for 60 years. I've owned just about every kind of quality guitar going and have played many others that I haven't owned. I've done repairs and set up on hundreds of guitars in the 50 years that I've been in the repair business. I have checked out MANY D-18 and D-28 Martin guitars that had the bridge located wrong. Some were over 1/8 of an ince out, usally short so that the guitar played sharp. I have found this problem in all other makes of guitars also.
I have always advised anyone looking to buy a guitar to travel as far as practical and try as many guitars as they can before deciding on one.
I agree with postings that say that a given guitar will sound different when played by different people.
I have played Taylor guitars, most of their higher priced models at least and most were fairly decent sounding and playing guitars. I just can't get the tone and volume from the Taylor guitars that I'm looking for. Some Santa Cruz guitars are good also but I find things I don't like with every brand I try.
I've found duds in every brand of guitar that I've ever tried. I still believe that overall when you compare same quality guitars from all makers that Martin comes out ahead.
I play a 1951 D-28 Martin that plays in tune all up and down the neck. I have a 2004 HD-28V Martin that sounds great and plays in tune all up and down the neck. I have a 2005 DCME acoustic/electric Martin that has a neck that feels like a Gibson electric. It is really fast. It also plays in tune all over the neck.
I was very upset when Martin started putting the Martin name on their line of cheap guitars. I think they should have kept the Sigma line for low priced guitars.
Anyway these are just my feelings about guitars that I've developed from 60 years of playing and comparing them.
Thanks for your time.