Long Vs. Short

There is a certain school of thought among writers that suggests that books considered a 'quick, easy read' are poor works of fiction at best.  While I understand the reasoning behind this, I personally disagree.
While it is often true that the 'quick, easy read' sort of books are poorly written, there are at least as many that are great works of fiction in their own right.  Consider film:  while it might be possible to condense a film like The Godfather down to about 90 minutes, it would not be nearly as good as it is in its proper running time.  Conversely, a great short film can't be stretched out into 3 hours without becoming boring, or even dissatisfying, at some point.  My point here is that stories take time to tell properly.  Sometimes this takes a lot of exposition, description, and various other techniques of the writer to let the reader fully understand the world that they're observing between the pages.  Other times, the story is simpler than that, so while explanations may be part of the story, they play a secondary role to the action and snappy dialogue.  When a writer mixes these two storytelling methods up, the reading experience is diminished, and can take a reader out of the story almost entirely.  If your secret agent is about to be shot by a hidden sniper, it's probably not a good idea to take a break to explain the sniper's backstory and motivation.  After the shots are fired, explain all you want to, and your readers won't be frustrated.
Getting back to my point, exposition is sometimes required for proper telling of a story.  This usually means that the story will become longer, and thus, more dense in terms of information.  A 'quick read' story concerns itself only with the pertinent facts, and doesn't take time to expand on smaller details.  I find that both approaches have their place, and are equally valid forms of storytelling.  A book that takes months to read can be just as entertaining as one that only takes a few weeks, or even minutes, in the case of short stories.  Personally, I like to balance out my reading between the long and short.  After something dense, such as Frank Herbert's Dune, say, I like to go with something a bit less dense, such as a pulp detective story.  One can be as satisfying as the other, and it's time people stopped judging books by thickness alone.