Mmm... I'm afraid I'll go off-topic... Know nothing about DV6 and DV4. Just what I read on an old Guild catalog.
But... I have a D4 made in Westerly R.I. in 1996. It's solid spruce top, solid mahogany sides and laminated arched back. One piece mahogany neck with rosewood fretboard and bridge. An honest guitar. Strong and well built.
Medium frequencies oriented, but balanced bass and trebles. Good volume (not too loud). IMO not a soloist instrument (that's what I'm not!), best suited for strumming (that's what I do!). I took away the Fishman undersaddle pick-up and put on a KK Pure Western passive under-the-soundboard one. Better amplified sound!
The neck is very comfortable. I also changed the nut and saddle with bone. Better acoustic sound!
I did other aesthetic upgrades (just my taste!).
Hope this is helpful. Good luck.