It’s almost getting monotonous.

Every new mounting of MERRILY WE ROLL ALONG shows that its many, many assets far outweigh its few liabilities.

That’s true of the mostly superb production now at the Huntington Theatre Company.

You’d never know that MERRILY was the 1981 musical that endured 44 painful previews and 16 not-well-acclaimed performances.

To be fair, MERRILY was substantially revised after its original short run by bookwriter George Furth and composer-lyricist Stephen Sondheim. The Huntington’s program cover even dares to proclaim that MERRILY is a “legendary acclaimed musical.”

What’s now in Boston is a replica of the London production that many of us saw on screen in 2013, courtesy of director Maria Friedman and The Menier Chocolate Factory.

Even Mark Umbers and Damian Humbley, who respectively portrayed composer (and sell-out) Franklin Shepard and bookwriter-lyricist (and collaborator/friend-turned-enemy) Charley Kringas, have now traveled to The Hub. Now those of us who saw their accomplishments on screen can now savor them in the flesh.

The show starts with Frank walking onto the stage with script in hand. The look on his face registers pain. Is he holding the story of his life?

Perhaps, for that IS what we’re about to see. “Party!” exclaim Frank’s guests at his Bel Air beach house. Everyone — including the young dazzler with whom he’s cheating on his wife — is there to celebrate the opening of the latest money-making (if mediocre) movie that Frank has produced.

Everyone but his old friend Mary Flynn, that is. Nothing good has happened to her since she wrote her sole best-seller. When asked what she does, she answers “I drink.” When then pressed to divulge what she really does, she says “I REALLY drink.” And when Frank brings over someone he wants her to meet, she puts her feet on the chair so that the person can’t possibly sit and get to know her.

Not until the next scene does someone nicer arrive: Charley, their longtime pal who’s turned the not-easy trick of writing a Broadway hit play that, we’re told, is also an important work of art.

Scene by scene, the musical goes back in time to show us what they all were — as well as their spouses, friends and acquaintances — before they became what they are (and never expected to be). Act One goes from 1976 to 1967; Act Two encompasses 1964 to 1957.

MERRILY is meant to make a stinging point – and yet a chorus member’s early pointed question — “How did you get to be here, Mr. Shepard?” — got the Huntington audience to laugh. So did references to abortion and Vietnam.

Could it be that Jonathan Tunick’s razz-ma-tazz overture sets up an expectation for Sheer Musical Comedy? Whatever the case, the show does become progressively easier to take as the characters youthen and let us see that they were once good people full of idealism.

Some audience members may even forget (or choose to forget) the characters’ later transgressions. MERRILY emerges as bittersweet, yes – but so is delicious dark chocolate.

Friedman’s vigorous direction keeps the show from ever flagging. Still, she should have ordered a projection that said “1976” at show’s start. Although the date is printed in the program, theatergoers can be pardoned for not noticing it. They’re well within their rights to assume that MERRILY takes place in “Time: Now.”

So some had to be confused a few minutes later when the title song established that the year was suddenly 1975. Did they assume that they’d traveled back a half-century earlier? If so, why did the characters look the same?

Was it Friedman or a techie who made the mistake of ignoring certain items that were hung on the back wall? Although that NBC logo is fine for Scene Two that takes place in a TV studio, it should have been removed when Scene Three took us to Frank’s apartment. Similarly, Scene Four begins outside a Manhattan courthouse, so The Great Seal of New York State is welcome – but not when the scene moves to the pier where Frank is embarking on an ocean voyage.

There’s nothing wrong with the stellar cast, though. Umbers has a native likability that keeps us from hating Frank; instead, he makes us want to understand him. The actor also provides a nice satisfied smile when Frank is alone, goes to the piano and starts playing the vamp of his greatest hit — as if he remembers what he’s capable of composing.

Humbley has a solid iron-fisted-velvet-gloved approach to Charley. He has a terrific moment after producer Joe Josephson interrupts a song that he and Frank are auditioning for him. After the criticism, Humbley continues singing, refuses to be discouraged, tries harder and snaps his fingers to convince the great man of the song’s worth. It’s a telling choice, so congratulations to Friedman or him for thinking of it.

And Mary? Eden Espinosa (who looks as if she could be Harvey Fierstein’s sister) avoids the pitfall of being nothing but obnoxious in the first scene; she skillfully manages to make her pointed barbs more funny than insulting. Later, when Espinosa sings that Mary wants life to be “Like It Was,” she makes us see her point to the point where we sympathize.

Some may question Christopher Chew’s low-life approach to Josephson. Let’s remember, though, that not all producers — not even in Broadway’s Golden Age of the late ‘50s and early ‘60s — were dapper gentlemen; some were just-out-for-the-money businessmen. Thus Chew and Friedman were in their rights to paint Josephson in this semi-vulgar light – especially considering that Josephson’s wife says the show they want Frank and Charley to write should be “fast, loud and funny.”

She’s Gussie Carnegie, played by the spectacular Aimee Doherty. What an astonishing trajectory she takes in going from Josephson’s secretary to his wife and star. The hot spotlight that hits Doherty in her second act opener isn’t nearly as hot as she.

Soutra Gilmour has provided little more than a white-walled and much-windowed unit set, so the addition of beanbag chairs during the ‘60s sequence got plenty of chuckles. Gilmour also managed to research and/or remember 20 years of fashions and got plenty of them into one show.

Furth layered in line after line in the early scenes that pay off splendidly. The one near the final curtain not only got one of the biggest laughs of the night, but also proved that the audience had been paying rapt attention.

Sondheim’s astonishingly clever and incisive lyrics sit well on his warm and melodic (yes, melodic!) music. But is there any place better than Boston for “Bobbie and Jackie and Jack”? Sondheim’s affectionate spoof of the Kennedys certainly resonates in a city where the family has never been off the radar. However, you could be from Pago Pago and still enjoy this one down to its last optimistic line.

MERRILY ends – or begins, if you will – with twentysomethings Frank, Charley and Mary on a Manhattan roof, binoculars to eyes, peering at the sky, trying to spot this new thing called Sputnik. But here’s the irony: The Soviet Union’s first artificial satellite was launched on October 4, 1957 – a mere week and a day after the Broadway opening of Sondheim’s first musical: WEST SIDE STORY.

Considering what has happened as a result of both events, no one would be guilty of too much hyperbole by saying that the world did change in an eight-day span.