every situation is different. Just as one would suspect, using a lav will give you a more "intimate" sound, but is that what your going for?
If your goal is to cut out as much naturally occurring reverb than a lav might be your best choice.
Keep in mind that your sound should somewhat match your picture. A little reverb isn't a BAD thing.
It would look/sound unnatural if you were on an extreme wide shot in a cathedral WITHOUT any reverb at all
personally, I would opt for a lav, just be careful about framing your shot for sound
More than likely a lav with be the best choice and I HATE lavs.
Closer to the source the better increasing the ratio between the voice and the background.
Rare situation where the quieter the subject is the better off you will be.
(less reflections)
I did a smaller spot last year for an out of state college where it took place in a gym.
Lets just say it was one of the most beautiful natural reverbs ive heard.
It had to have a decay of 10seconds. No joke. It was so strong that
if you yelled to someone 20ft away they couldnt even understand what you said
because of the mess.
I tried numerous overhead mic's, decided to go with the lav in the end with pretty good
results. (i can pm you a link to the spot if you want to hear it)