Well, our Don Quixote delivers the song, in abundance. It is not unusual for his forthright performance of the number to stop the show with lengthy, well-deserved applause. Tom Simpson is spectacular in the role; the challenging score sits beautifully on his voice, and he has made acting choices which fully flesh out this character. His performance moves seamlessly from the aristocratic storyteller Cervantes, to the eccentric nobility of Quixote, to the heartbreaking fragility of the delusional Alonso Quijana. Tom is a DC actor known primarily these days for his work in musicals, but I can attest that he is also a first-rate dramatic actor. It is a privilege to stand next to him throughout the show.
Neither Mitch Leigh nor Joe Darion was able to recreate their La Mancha success in other projects. Composer Leigh returned to Broadway with the musical telling of the Odyssey legend in Home Sweet Homer, a notorious flop which opened and closed in a single night, despite the star power of Yul Brynner in the lead (not by coincidence, Joan Deiner, La Mancha's original Aldonza, was the show's leading lady). Lyricist Darion did little better with Illya Darling, the musical version of Never On Sunday which starred the original film's Greek beauty Melina Mercouri. Unfortunately, she was paired with (get this) Orson Bean as her romantic leading man, and that show failed as well.
But nobody really cares about these guys' later failures. Folks still remember Man of La Mancha primarily through its music, or rather, through its huge central ballad. And who am I to quibble?