When I went to check out a D15 some time ago (which I ended up buying) I did so expecting it would be a poor man's D25.
Boy, was I surprised! It may even have the edge, soundwise, on my D25.
The only dfference I can see between the two models is the addition of top binding on the D25 and the MOP overlay Guild headstock logo on the D15, which I think is more attractive than the silkscreened logo on the D25. Anyone aware of any other differences?
Something I noticed: unlike Guild's other models, the top braces don't go under the kerfing and to the edge of the top on their mahogony-topped guitars; rather they thin out about 1/2" before.
This may be one of the main differences between Guild's mahogony-topped guitars and their other models.