Although not Bowers's primary focus here, the value of both Chaucer and Langland must ultimately rest on their artistry. Both wrote in an older English which, like a strong foreign accent, takes some getting used to; but Chaucer appeals immediately because of his sly wit. He is a wonderful storyteller who, especially in the Canterbury Tales, presents us with memorable characters and stories for any taste: from epic romance, to personal confession, to bawdy comedy, to devout saint's life.
By contrast, readers of Chaucer coming to Piers Plowman are often put off by the alliterative poem's length (which is not easily excerpted) as well as by its allegory, interrupted narratives, and moral seriousness. Bowers declares that modern readers "seldom admit great enjoyment" from reading Piers and that "probably no undergraduate has wished it longer."
What Benson elegantly describes as "sly wit" I'll put in a more vulgar way: Chaucer is way funnier than Langland. All these centuries later, and readers of the "Miller's Tale" still laugh so hard that their cheeks hurt afterward.