You get the same guitar, just that one has a pickup built in. We have had several threads before on pickups and onboard electronics which can be easily add and there are some which people prefer over factory setups.

The necks are the same low oval profile.

I have said before here as had Dan and several others that I prefer the OOOO which Martin called M for awhile. The body shape is quite similar, just a bit less depth. An awful lot of people agree that the OOOO has the best balance of any Martin. Considering your style and sound you are after, it may be a good choice. Check the OOOO-1 GTR at ELDERLY and have a look. It has the same neck dimensions and shape you are after, spruce top, mahogany back, laminated sides though (not a big deal), and uses the satin finish all over instead of having the gloss top. Its worth a look and some consideration.

Spaw