The Martin sounds like a typical rosewood dread, though a little muffled almost like it needs new strings. The Gibson is bright, clear and more articulate without the "tubby" sound that big maple jumbos can have. Neither is better, just different. I'd still go for a 12-fret mahogany dread over either of these as my first choice.
I think they are both nice for inexpensive beginner guitars.
The Gibson sounds much better during the finger picking segment. There is less of a difference picked, but i'd still give it to the Gibson. This will vary depending on whose playing them.
Either one would be fine, thank you!