My latest test of acoustics is to listen for the overtones, the sparkle in the hi end 1-2-3 octaves above the note your playing. Each note will have way more content to it and that needs to harmonize too! Hard to explain but once you've played a guitar that "rings like a bell?" you'll know. 
Certains name brands seem to put out more than other , but you can pull 10 of the exact same guitar down off the wall and only one of them might pass this test. 
 
I have a Art and Luthier and now a Taylor Mini GS that passed the test, the Taylor was one of 10 that didn't pass. 

Darn-nabbit, these acoustics are making me sing better...
 
 
 
 
...or maybe it's all the practice I've gotten in the past week. :-)
 
 

"the sparkle in the hi end 1-2-3 octaves above the note your playing"
That's where the Brazilian Rosewood shines!
"you can pull 10 of the exact same guitar down off the wall and only one of them might pass this test"
Sad but true!
Lots of things factor in here, meeting production quotas probably not so much...
 
T

DeeringAmps
Acoustic guitars NEED to be played to "open" up.
Bob Benedetto gave a seminar at the Luthier's Guild annual event some years ago, and spoke at length about it.
The more it vibrates, the better it vibrates.
Tom

True that.
I have a Simon&Patrick Woodland Cedar that I routinely thrash. It loves to be played hard, even though it has a naturally warm, somewhat mellow tone.
My recently acquired Martin D-18 is noticeably brighter, as expected with a Spruce top. She has been in the case for the past twenty years, but there are signs she got played vigorously for the first twenty. And she definitely has some life to her.
Oddly(or not), I don't really favor one over the other. They have distinctly different personalities, and I love them both.
The key thing here is they both get played a lot, and that really does seem to affect how the wood behaves.

My Nephew has a little Simon and Patrick folk or Parlor, It is so thrashed and he never changes the strings, but you just can't put that thing down. I think it is like this because he play's it 24/7
It just can't help but play nice. I guess you can say it's "played in".  

 
Boy, some you sure have access to some nice guitars.  Thanks for sharing your experiences.
 
My folk and my daughter's ex-parlour guitars I mentioned in another thread were both Simon&Patrick sunbrust cedar tops.  They don't seem to be made anymore.  They're nice but the frets are really soft.  Mine needs refretting after not that much playing, say an hour or so a day for 2-3 years, but I wouldn't pay someone to do it.  Another project for the future.