All else being equal, for standard city commuting and light to moderate touring, which is preferred?
Also, anyone have opinion re the Jamis Coda Elite?

The distances you are planning traveling will determine the answer to your question more than anything else. For rides of 50 miles or less, I don't think the frame material will make that much of a difference. It also depends on how the bike manufacturer designed the frame and the type of tubes used.

I have a Jamis Quest, and I really like it. It has drop bars and a carbon fork, and a Reynolds 631 frame similar to the Coda. I suggest a visit to your local bike shops to get an idea of which bike fits you the best and to test ride some bikes.

http://www.jamisbikes.com

All else is usually not equal,and even at that, they would have to be same diameter ,butting and built by the same guy. That being said,631 is a bit stronger and might make a slightly lighter frame.It's air hardening,meaning it looses no strength during welding or other fabricattion like 520 can. In a real world blind test you couldn't tell the difference based on alloy. If you are heavier or bigger,oversize tubing would be a plus.

I'd go for Reynolds, like the Vigorelli, Imola or Eros
Corsaire

Reynolds 631 or 525