I agree 100% !Wiley's Soapbox:
For the best sound on an acoustic guitar, a good mic beats any pickup you can put in a guitar, no matter what your playing style is.
Most pickups are little synthesizers that are programmed to sound (sort of) like a guitar -- but not neccessarily your guitar. A good mic captures the actual sound quality of your guitar, which pickups do not -- and I bet that D40 sounds fantastic.
This is my opinion, but it's based on four decades of listening to guitars in live settings with miserable sounding pickups. I've never heard one yet that sounds like an actual guitar sounds, which is strings moving wood moving air. Pickups also tend to flatten nuance -- dynamics are less dynamic.
The only drawback: if you like to hop around while you play, it's hard to do that AND stay on mic.
The truest acoustic guitar sound is achieved with external mics. Undersaddle pickups are always artificial sounding no matter how they are processed.