On one perch you have the Osmond faithful, who have grown to middle age with the family and who hold up dolls or old 45 RPM singles at the foot of the stage. They know that Tiger Beat heartthrob Donny, now 50, will treat his old anthem "Puppy Love" with the proper blend of winking humility and sincerity.

These fans keep up. They might even come in knowing Marie, who turns 49 this month, has taken opera lessons and tackles Andrew Lloyd Webber's "Pie Jesu" from the classical "Requiem."

To this camp it's no surprise that both siblings are at the Flamingo Las Vegas looking just right, in strong voice and balancing their still-youthful presence with a subtle dusting of age and experience.

On the other side are those who have been away, and come to this reunion expecting an epic cheese-tacular. An awesome glob of Velveeta melting from the stage like blood rushing through the elevator doors of "The Shining." A tidal wave of ballpark nacho goo 40 stories high, or at least as big as "the little poster of us on the side of the building" Donny jokes about in the show.

I'm not just talking about those rare souls who would pay a hundred bucks to goof. In this hard economy, there would be only a smattering of those like comedian Kathy Griffin, who promised a few months back to be at her "judgiest" when she catches up to the Strip's new resident headliners.

No, I'm saying there are perfectly straight-faced customers who really don't want to see the kids act all grown up. They fully expect the canned banter, the cue card Bob Hope sketches, maybe even goofy production numbers of today's hits. ("I Kissed A Girl" anyone?)

All of those are in fact genuine memories of Donny and Marie, because their TV variety show marked their greatest fame as a duo. So who could blame anyone for mild disappointment that the insults seem half-heartedly slung? Or that after only a couple of songs, the two split up for long solo sets -- around 25 minutes each -- making for a long wait before they are together onstage again?

At least the wait pays off. Fromage abounds in a full-on production of the Stray Cats' "Rock This Town," complete with black shirts, white ties and dancers in full "Guys and Dolls" regalia.

Costuming the dancers in Disney Channel hip-hop also brings the Sid and Marty Krofft touch to a medley of "Get Ready" and "Dance to the Music," the latter featuring Donny on air bass. And Marie's version of "Cabaret" is rescued from respectability when dancers bound onstage dressed like Freddie Krueger.

More of the show is in the spirit of compromise, bringing the Great Divide together and reconciling the Osmonds of then and now. Marie wears a vampire-chic waistcoat and climbs around on a jungle gym to the Eurythmics' "Would I Lie To You?" But damn, that girl sounds good. Likewise Donny and the crackling stage band on a Stevie Wonder medley. It isn't as funny as it sounds, even when he sings that "I Wish" line about "when I was a nappy-headed boy."

The show has way more personality than the overblown Cher spectacle across the street, though a climactic "dance off" meant to capitalize on Marie's "Dancing with the Stars" popularity doesn't quite bring it all home.

It's sure to smooth out more in time, as the two get used to working with each other again. After all, this run looks to be a hit for as long as they want to keep it here.

But if the siblings wear thin on one another, and the stage snark becomes more genuine? All the better still, at least from the cheese side of the Divide.

Contact reporter Mike Weatherford at mweatherford@reviewjournal.com or 702-383-0288.