Believing in life after love turns out to be a surer bet than pinning your hopes on jukebox musicals, no matter how fabulous the subject. The Cher Show, opening tonight at Broadway’s Neil Simon Theatre, might not disappoint anyone likely to applaud a Bob Mackie-designed Oscar gown, but neither does it do any boundary-pushing. So very un-Cher.

With a pedigree promising much, much more – book by Rick Elice (Peter and the Starcatcher, Jersey Boys), direction by Jason Moore (Avenue Q), costumes by Mackie and the involvement of the diva herself as producer – The Cher Show doesn’t budge outside lines already drawn for other mediocre bio-musicals, dragging Cher where Donna Summer, Gloria Estefan and even Janis Joplin have already been. The lack of creative ambition and innovation is dispiriting, especially when Jersey Boys, Beautiful and Lazarus have already proven these things needn’t be dreadful.

Though superior to the holier-than-thou Summer, and at least a bit less sanitized than A Night With Janis Joplin, The Cher Show still can’t bothered with new ideas. Multiple actresses playing the title star? Check. IMdB-deep bio-highlights? Check. Songs shoehorned as dialogue? Sound-alike concert performances? Vegas-production dance-floor lights? Check, check and check. The Cher Show, like Summer, even has a late-in-the-game spectral visit to tidy up life’s leftover messes. Sonny Ex Machina.

Even its successes feel familiar: Like Summer and Janis, Cher boasts a powerhouse performer giving a powerhouse performance in the central role. Or, rather, the central of the central roles, in this case singer-actress Stephanie J. Block as the mature, wised-up version of Cher. (Her character is listed as “Star”, while Teal Wicks plays the ’70s variety show-era “Lady” and Micaela Diamond is the ’60s mod-with-bangs “Babe.” Wonder if they’ve met Summer‘s “Disco,” “Diva” and “Duckling” Donnas?).

Block does Cher nearly as well as Cher does Cher, from the vocal impersonation (both spoken and sung, the latter with, intentionally I’d bet, pitchy lower register and all) to the famous tongue flick and hair swish. As convincing as the other two Chers are, they’re place and show next to Block’s win. The difference, to paraphrase Mark Twain, between lightning and the lightning bug.

Together or singly, the Chers hit all the songs we could want, sometimes in keeping with historical chronology, sometimes not. “If I Could Turn Back Time” kicks things off so Star can do just that, while 1965’s everlasting “I Got You Babe” arrives later than a 1973 hit, allowing little, dark-haired Cherilyn Sarkisian to tell mom (Emily Skinner) all about a bully’s cruel taunts. “Let me tell you a little story,” comforts mom, launching into ’73’s “Half-Breed.”

The stitching doesn’t get much subtler than that, but the songs are almost uniformly well-performed, at least by the Chers. “Believe,” “Strong Enough,” “You Haven’t Seen the Last of Me,” “Gypsys, Tramps & Thieves,” “If I Could Turn Back Time,” “I Found Someone,” “Bang Bang (My Baby Shot Me Down)” are fine and dandy.

And it’s no surprise that the tale doesn’t hit full steam until the arrival of Sonny Bono (played by Jarrod Spector, and wigs), and even then the impact doesn’t really amp up until the duo appear, in full hippie regalia, on Britain’s Top of the Pops, singing the song that would become their first hit and forever theme. Spector’s first few notes of “I Got You Babe,” delivered, at last and unlike his speaking voice, in full-on Sonny mode, drew a sustained round of applause at the previewed performance.

The rest of Act I follows the Sonny and Cher story that played out in headlines of the day and retellings in the decades since – hit TV show, marital discord, divorce, Gregg Allman, failed solo TV shows, a failed reunion TV show, and, for Cher’s second and third and fourth acts, success and respect as an actress, Oscar nominations, an Oscar win, Oscar gowns, the bagel boy relationship. Just one comeback and triumphs after another, really, providing any telling of her story with more than enough material. (All that’s missing is 1987’s Sonny and Cher reunion on The Late Show With David Letterman, and that’s a real shame).

So why does The Cher Show feel as skimpy as a Mackie dress? Part of it, no doubt, are the cartoonish non-Cher performances. Spector, Skinner and Michael Berresse pitch their performances as Sonny, Cher’s mom and Mackie himself to somewhere about a block away – but they’re the very essence of nuance compared to Matthew Hydzik’s silly Gregg Allman and Michael Fatica’s sillier Phil Spector. An impossible-to-imagine duet on “Dark Lady” between Sonny and Gregg does no one any favors.

It’s unlikely director Jason Moore is trying for historical accuracy or authenticity here, but much of The Cher Show wouldn’t pass muster as the ’70s-era variety sketches that the Bonos did so much to create. Nostalgia thrives on pinpoint detail – the sort that draws that audience “awww” when Sonny starts to sing – and The Cher Show flashes those moments only intermittently, just like a lightning bug.