Joel, I personally prefer, as I've said, a bit larger guitar than the Martin Backpacker because sound is very important to me. If you want those bass strings to actually get heared as they should you need a larger sound box and that takes up space.
I wonder if someone will invent a folding guitar, that the sound box can be folded without compromising the sound :-).
Regarding the reviews you've heared/seen on the Martin Backpacker guitar, I've looked at Harmoney Central, a web site specializes in music (it also got a large collection of tabelture and chords files for a lot of songs) and you can see the reviews here. As you can see, they are not that bad.
