Having played a Taylor for years, my first reaction was, "sounds like a Taylor". The Martin also "sounded like a Martin" to me and the Guild sounded like a Guild. That's probably easy to say with my eyes ruining the surprise, but I've never really liked the Martin sound.
He was so correct in his take on all of them. The Martin was "good for bluegrass". The Taylor was "bright", (as always). He waffled on the Guild but seemed to like it.
He fumbled a little with his fingering on the Guild, due to the different fretboard. Most of those guitars have a flatter fretboard radius, with the strings spaced a little closer together.