I was really skeptical that it could top Shakespeare's but I think it has, although their takes on it are completely different (Shakespeare was much more pitch-black cynical). Chaucer's Troilus is a real anomaly... I guess you'd call it a Verse Narrative Drama, but calling it a "chamber epic" might be more appropriate. It's 8000 lines, which is only 2000 short of Paradise Lost, and it is narrated rather than written in dialogue/monologues, but its division into 5 books, which follows the classic dramatic structure almost perfectly, as well as its tight focus on 3 central characters, puts it it squarely in the realm of classic drama. Whatever the case, it's a superb amalgamation. I can see what drew Shakespeare to it as Chaucer's main interest is on the psychology of his characters and the multitude of tangential themes (like free will VS predestination), as well as the ability to make comedy, tragedy, poetry exaggeration, sobering realism, lightness, heaviness, elegance, and clumsiness trip side-by-side.
The extended length allows Chaucer time and space to break everything down to the minutest details, really chronicling the entire psychological process of falling in lust, falling in love, falling out of love, and suffering heartache, and that extensively deep intimacy, rather than general broadness, is what makes it so extraordinary. I guess many would call it boring because there's very little superficial action. The entire first 2 books consists of nothing but Troilus falling for Criseyde and Pandarus running back-and-forth between them trying to convince Criseyde to give the guy a chance. They don't even really meet until Book 3, over 3000 lines into the proceedings. But what some would call boring I'd call patience and attention to detail. When they finally do get together the pages explode with some of the loveliest erotic/love poetry every penned. Chaucer knows how to build to a climax and then release it all at once. The breakdown of Books IV and V have been just as riveting, and Chaucer writes the way things fall apart and unravel with as much complexity as how they develop and come to fruition.
I guess it's a bit hard to compare T&C to The Canterbury Tales or Chaucer's Dream Poems because they're all so different, but, right now, I think T&C is my favorite work from him. TCT is a sprawlingly awesome achievement, but it's incomplete, fractured, and uneven, with its low points being as terrible as its high points are transcendent masterpieces. I think it's a bit difficult to really consider as a whole because it's so diverse. I will say that T&C is better than any single Tale. If I was forced to choose between them for a desert island trip it would be more difficult... I might take TCT just because of that awesome, if flawed, diversity. But T&C is Chaucer's "artistic perfection" masterpiece where everything is in its right place, shined to a magisterial greatness.