In the realm of stage musicals, Cats has taken on the role of the quintessential love-it-or-hate-it show — with cool cred going almost exclusively to the haters.

And yet Cats ran for 21 years in London and 18 years on Broadway, while touring and regional productions continue to pounce on theaters around the world.

Clearly it speaks to someone.

Before we get to the film, let’s shake off the hindsight of knowing Cats is one of the most successful musicals of all time. Instead, let’s time-trip back to 1977 when Andrew Lloyd Webber — who had scored the hits Jesus Christ Superstar, Joseph and the Amazing Technicolor Dreamcoat and Evita, all with lyricist Tim Rice — was experimenting with going solo.

Well, not exactly solo. As an exercise, he tinkered with putting tunes to poems by T.S. Eliot, hardly a move made by someone whose intent was to create a show that would run for decades. The experiment originally didn’t even have the thin strand of plot that ended up in the full-blown musical. It was more of a variety show than a traditional musical.

However, seeing potential in it, producer Cameron Mackintosh and director Trevor Nunn jumped in and pushed for some semblance of a story. More poems were found, including one about the once-glamourous, now down-on-her-luck Grizabella and others that referenced a Jellicle Ball cat party and a feline afterlife spot called the Heaviside Layer. Material was cobbled together from different sources. And the show grew.

And grew.

And growled.

What ended up onstage was primarily a dance piece. Combined with an immersive junkyard scenic design, fully committed costumes and reverse-anthropomorphized choreography, the show struck a nerve with audiences (if not with many critics). It carried the tag line “Now and forever,” and for a long while that didn’t seem like an exaggeration.

That version has already been filmed, with some strategic gaps. If you want some sense of what it was like on stage — but without the risk of Rum Tum Tugger climbing onto your lap — a version was released to home video in 1998.

If you discount that video production, Oscar-winning director Tom Hooper’s cinematic Cats may be the longest gap between a stage musical’s premiere and the opening of its first film version at 38 years (which would be like the movie version of The Sound of Music not hitting the big screen until 1998).

And the result is …

Curious.

Frustrating.

Lame.

At times, beautiful.

And certainly one of a kind.

Where to begin?

In its effort to add a stronger strand of plot without altering the tone and spirit of the original, Hooper’s Cats has more in common with Milos Forman’s Hair than with most stage-to-screen transfers. Dialogue has been added, songs reordered and characters given new purpose.

The idea that elder cat Old Deuteronomy will pick one of the cats at the Jellicle Ball to send off to be reborn is still intact. (Yes, newbies, that’s pretty much the plot of both the stage and film version.) In the movie, though, it’s made explicit that a variety of feline attendees are auditioning for the transformation. Meanwhile, evil cat Macavity systematically vaporizes them and transports them to a barge. The change gives a bit of forward motion to what was essential a series of music-hall turns.

In another major change, Old D. has been given a sex change and is now played by Judi Dench, who gives Deuteronomy not only dignity but also strong hits at her randy past. (Dench can pull that off without the help of lyrics or dialogue. Side note: Dench would have played Grizabella in the London original if not for a torn tendon. Instead, the part went to Elaine Paige.)

Deuteronomy isn’t the center of the story, though. Hooper and his co-writer, playwright Lee Hall, have also given us a set of outsider eyes through which to watch this story. The stage’s relatively personality-free Victoria (the white cat) here provides much of the POV. Early scenes find her abandoned in a strange neighborhood before she’s taken under the wing of friendly cat Munkustrap and introduced to the Jellicle goings-on.

Visually, there are wonders and blunders to behold throughout. Hooper has rounded up some world-class dancers, including former New York City ballet lead Robert Fairchild, but too rarely allows us to actually watch dance. Instead, frantic cutting is the norm. That worked just fine in Chicago but not as well here.

An exception is when Hooper gives Jennifer Hudson the treatment he gave to Anne Hathaway in 2012’s Les Misérables — allowing her to sing, for the most part, in snot-laced close-up. It works here in part because Hudson is truthful and deeply vulnerable while also sounding great.

In other high-profile slots, Taylor Swift’s showcase number is in the Moulin Rouge! mold and is fine for what it is. However, the original song she co-wrote for the film doesn’t even remotely fit in with the rest of the score, with on-the-nose lyrics that dramatically contrast with those from existing material. Her undergraduate work feels awkward in Professor’s Eliot’s anthology.

Jason Derulo doesn’t make much of an impression as Rum Tum Tugger. James Corden and Rebel Wilson each get a turn doing variations on fat cat jokes and making feline puns that would have made Eartha Kitt toss a hairball. As Macavity, Idris Elba looks maybe a bit too naked in his skintight costume, and the contrast of dark equals bad while light equals good makes for some unintended uncomfortableness.

The scenic design is a constant wonder — which doesn’t mean it’s all good. Trying to pack spectacle into every frame often creates visual exhaustion. As often as it enhances, it also takes away from the emotional core of the characters. The vibe is creepier the further the camera gets from the actors and the more they are manipulated by CGI and stunt effects rather than making magic through song and dance.

But just when it looks like Cats has gone completely off the rails, something quite right happens.

Among those rights: Ian McKellen’s heartfelt and heart-wrenching take on Gus, the theater cat.  It’s a role John Mills handled beautifully and simply in the 1998 video and McKellen, with a bit more screen time, is equally powerful. He speaks / sings of past-glory memories through a body that’s no longer cooperative. As with Hudson’s Grizabella, memory provides the gateway to both pain and joy.

For audiences, the percentages of pain and joy will no doubt vary wildly — such as it is with Cats … now and forever.