I have an old Yamaha that I still prefer to the Guild monster that I just bought...the Guild wails, and is really well made, but my old Yamaha somehow has the kinder sound, especially when strung with fingerstyle silk-and-steel. It's all wood too.
Now I've played an OLD Martin before, and I do have to say it does make a big difference. On old Martins, the tonality is far richer from being played, the way a very well made and old German violin will have a piercing and beautiful tone. This is mostly based on the grain of the spruce in a guitar's top, as well as the back and sides also being solid wood and not laminated. Modern acoustics nowadays are laminated, but since most of them have tinny internal pickups, it doesn't really matter when they're plugged in. A lot of internal pickups sound the same regardless of the brand of acoustic guitar, unless you're using a K&K pickup, which is by far the best on the market.
When you're playing a well made acoustic with a K&K pickup, such as an old Martin, a better Spanish classical, etc. etc., your sound will blow any other old acoustic setup to bits.
Price does not necessarily mean quality. If you find a weatherbeaten Yamaha (or Alvarez, or Epiphone) that's at least twenty to twenty five years old, several of the pegs are loose, it needs a new bridge, and somebody's asking two hundred for it, then in my opinion haggling is negligible. I would take that old guitar and get it fixed, (as long as the neck's fine), stringing it with silk and steel. This I would take, even if a newer model Martin were the same cost. Which they're definitely not.
These older guitars are often made so well, that any made nowadays in the same fashion would cost three, four times as much.
And, by the way, K&K pickups are often cheaper than the usual pickups on the market; they're fantastic.
Alliekatt