“If/Then”, the Broadway musical that opened the other night at the Pantages Theater in Hollywood is a very mixed bag. It stars a delightful lesbian couple (LaChanze and Janine DiVita), and an earnest gay couple (Anthony Rapp and Marc Delacruz), and the fabled Idina Menzel, whose character can’t seriously commit to anything. She even has two names: Liz, to identify her fun side, and the businesslike Beth, to acknowledge her Ph.D. in Urban Planning.

A marvelous bouncy chorus sets the pace as they introduce the theme, a paean to Fate, Chance, and Choice. Liz/Beth is skeptical until she meets a just-returned-from-action soldier, Josh, three times in a row. “It’s a sign,” sings the chorus, “It feels like a fateful day,” and Liz/Beth reluctantly submits to her inevitable fate.

Perhaps it was opening night jitters, but Menzel’s performance was uneven at best. She has a glorious voice, but at times it was shrill or loudly raucous, a la Ethel Merman. And even though she was heavily miked, her enunciation was unclear and she was often difficult to understand.

The other singers, however, are perfectly wonderful. Especially Anthony Rapp, who plays Lucas, Liz’s long-time friend, and James Snyder as Josh, the fateful soldier. But the real star of the show is LaChanze, who plays Liz’s newest friend with a passion and verve that brings “If/Then” to vibrant life. (These three are the original stars who played the roles on Broadway.)

Tom Kitt provided the music, which is not quite memorable (you won’t leave the theater humming the tunes) and Brian Yorkey is responsible for the book and lyrics, which are contradictory and confusing as Liz/Beth lurches between her two personas and her multiple choices.

The whole plot, in fact, deals with Beth’s rapid rise to the top position in planning for the city of New York versus Liz’s desire to remain an activist (she helped Lucas lead a march to protest the city’s building of new apartments for the rich as opposed to housing for the poor) and to become a school teacher.

Beth is egged on by her boss, Stephen, (Daren A. Herbert), however, and follows him as he moves up the ladder in city government.

And all the men (and some of the women) are in love with her, of course.

The conflict dogs her through the play and even her feelings of love are inconsistent and ambiguous.  But all the plots and subplots of this very long production are more than counterbalanced by Larry Keigwin’s rambunctious choreography and the spectacular set design by Mark Wendland and even more spectacular projection design of Peter Nigrini and Dan Scully.

The projection design consists of a background of ever-changing architectural drawings and maps of the city, subway markings and the like, plus actual sites like the triangular Flatiron building. There is also a fabulous sequence in which passengers on a subway train appear to be moving at great speed as the image of an actual train speeding in the opposite direction fills the background.

The set, too, is innovative, with revolving rooms that move to the foreground and to which the principals retreat as the action unfolds.

The pace is fast, and Michael Greif’s deft direction encourages the viewer to overlook the weaknesses and the lack of coherence of the script. All in all, though, the show is well worth seeing, mostly for its production quality and its spirited dancing and singing.

“If/Then” will continue at the Hollywood Pantages Theater, 6233 Hollywood Blvd through Jan. 3, 2016. The performance schedule is Tuesdays through Saturdays at 8 p.m., with matinees Wednesdays, Saturdays and Sundays at 2 p.m. There will be 2 p.m. matinee performances on Thursday, Dec. 24 and 31, but no evening performances on those dates. In addition, there will be 7:30 p.m. performances on Sunday, Dec. 27 and Jan. 3, and no performances on Friday, Dec. 25 and Jan.1.

To order tickets, call 1-800-982-2787 or order online at HollywoodPantages.com or Ticketmaster.com.