Indeed, the reputation of the book overshadows the book itself. The very notion of a great book, especially one regarded as the great American novel (Moby-Dick is), is likely to scare away readers. A shame, because good books, not only great ones, ought to be enjoyed.
Moby-Dick is a pleasure to read. A passive narrator, writing under an assumed name, recounts a whaling voyage he took in which the ship and crew were lost to sea on account of a Great White Whale. And were it not for the monomaniacal pursuit of the Whale by the captain, a Quaker named Ahab who lost his leg to the selfsame whale, then the crew might not have perished.
As for the reading experience, the delight is in the details. The book is largely written as though you're engaged in a conversation with a talkative sailor who wants to let you know exactly what whaling is like. He wants to tell you everything he knows about whales, the true accounts and legends alike.