I'm buying the DR-500M right now, but I'm wondering, what exactly is the difference? I played both last night, they sounded pretty similar...the AJ might have been a little more mellow. DR sounded pretty bright and I liked that. Also, the DR felt a little better to me...not sure why. They both looked the same size.

Anyway...just wondering what exactly the difference is...
the difference is the body shape. the AJ is built more like the Gibson Jumbos(which were built somewhat as rivals for the Martin Dreadnought body guitar). the DR is a copy of the Martin Dreadnought itself.

other than that, the aesthetics are slightly different.
the dr has binding therefore it felt of a higher build quality ? :S i have limited experience with acoustic/classical but it says on the page the dr has binding
binding doesnt necessarily imply higher build quality. binding is mainly an aesthetic thing.