The "read" is different. Dragon is a very leisurely read to me. The articles are generally short, and the Headline Articles, Demonnomicon, or the Faith articles are always entertaining, and worth a read. I do not use Greyhawk gods, and yet I love the level of detail in the articles, file off the serial numbers and you have instant depth.
Bazaar of the Bizare is a classic and storied feature, and the magic items presented are often quite good. Zogonia is always good, OOTS in Dragon, while not as funny as the online version, is more stand alone. I pretty much read all of Dragon on the day it arrives, and it is pure indulgent bliss, just me and my hobby, for no other reason than it brings me joy.
Dungeon is much more the buisness end of the DM's job for me.
Even when I do not like a presented adventure, I feel compeled to go finish it, because I am combing the magazine for an encounter, a map, a stat block, an idea that I might steal, get inspiration from, or use. Now Dungeon is great, and worth it's weight in gold and larvae, but Dragon to me is like watching a game on Sunday Afternoon for no better reason than you want to.