New or old is better.

[Nightclub Dwight]

As for the age thing, there is supposedly a molecular change that vibration causes in wood through repeated use (i.e. over a couple decades). You can actually have the Gibson custom shop vibrate the guitar for you without relicing, I've been told. The same person told me you can set your guitar on a subwoofer for 24 hours or so and achieve similar results.

This is more talked about with acoustic instruments than solidbody electrics.  It makes some sense with an acoustic, but I know the limiting factor for my own tone will usually be my own abilities rather than my equipment.  I'm simply not a good enough guitarist for it to really make a difference one way or the other. 

 

[-CB-]

guys, any truth to the claim that over a period of time (years) the paint is absorbed by the wood and the guitar resonates/sounds better? or about "aging" of wood?

Not absorbed.  Shrunken perhaps.  Some folks claim... and claims are just that... that thin finishes, nitrocellulose finishes, shrunken finishes, checked finishes, red finishes that have turned brown, worn finishes, gold finish that has turned green, you name it... are better.

I say doodlysquat, except maybe, on an acoustic top where you really want that finish to be part of the total tone of the guitar.  That is - the soundboard is what's creating the most of the tone and to the most extent, the volume of the guitar.  Spruce, fine grained, close grained spruce is used because it is strong, and you can get a very thin and resonant plank, and still retain the strength with minimal bracing.  When you have the top of the guitar creating its unique tone and envelope, you really dont want to smother it with a thick poly finish.  You can go thick on the body sides and back, but the top must be free.  Finishes like shellac, and nitrocellulose have been favored since they can go on very thin, be an acceptable finish, be easy and inexpensive to work with, and not detract from the tone.

There are those who insist, as a point of Biblical infallibility, that Gibson Les Paul faded guitars are better sounding than Les Paul standards, because of the thin finish.  Sigh.  Doodlysquat.

 

[-CB-]

As for the age thing, there is supposedly a molecular change that vibration causes in wood through repeated use (i.e. over a couple decades). You can actually have the Gibson custom shop vibrate the guitar for you without relicing, I've been told. The same person told me you can set your guitar on a subwoofer for 24 hours or so and achieve similar results.

Molecular change...  then there are the cryo treated pickups, frets, necks... tubes... anything anyone is willing to pay for.

I will say, that I used to break in Eminence 10's with my HP tone generator, set at about 45hz running about a quarter watt.  Threw a moving cushion/pad over them, its damned annoying.  The thing with that though, was the spiders and surrounds were really tight on those otherwise great speakers.  Folks would get them and say - aaak they sound like glass breaking!~  They needed to be loosened up.  Maybe there's something to all that shaking and dancing.