A PHX institution and rightly so.
Just basically straight up one of the best sandwich/lunch places in the whole Valley. I always make sure to stop in on any visit back.
They have great coffees, cheeses, meats, and other gourmet selections as well...pretty much always worth the splurge while you are there.
If you have a chance eat there if possible. There is something wonderfully lazy about spending an hour or so at D&D...the beer and wine bar may add to this...as well as the decent patio seating.
I really can't expand too much on this very sparsely written review. They do what they do...and they do it very well.