Hi.. I"m currently going through a similar thought process - I've had a Guild D55 since the early 90's and have always LOVED it, but am approaching 45 and considering treating myself to a Martin. I've played the D41 and D28 (not the D28V with difference bracing) and I wasn't blown away at all with the Martins. Obviously they're different guitars, so I don't expect them to sound similar, but to me, my Guild just sounds so much fuller and richer. As others have said, it also feels a bit more solid, which I personally like, but aside from the weight and feel, to me, the Martins just didn't sound on par - which I was really surprised with. So now, instead of purchasing a Martin, I'm considering upgrading the electronics in my existing Guild D55 from the 20 year old Fishman piezo to the latest Fishman Aura Pro to improve the live sound from the guitar.