This is the difference between a well-plotted reality show and one that eats its young:

American Idol followed a week in which front-runner Adam Lambert was nearly ejected with a theme tailor-made for the bionic-throated glam rocker -- a rock night featuring an Idol first, clearance to sing a Led Zeppelin tune.

Predictably, Lambert knocked his performance into the stratosphere, savoring the glass-shattering final note of the Zep's Whole Lotta Love like the competition-ending display he surely meant it to be. And because he sang first, judges spent the rest of the night telling the remaining Idols how their performances failed to match his.

ABC's Dancing With the Stars seems to be taking another tack, offering a results show Tuesday in which one of the competition's strongest competitors was ejected, rapper Lil' Kim.

It's hard to imagine a reality where a cardboard stiff rodeo star can beat out a woman whom  judges accused of having a "bionic booty," but viewer votes cast off Lil' Kim after a set of dances Monday that were, admittedly, not among her best.

Each cycle, Dancing loses a front-runner, either to an explicable vote or injury. But those losses usually happen earlier in the competition. It's tough to put much stock in a dancing competition where one of the better dancers gets voted off without making any obvious mistakes -- just another reason why this show can be so frustrating to watch, week to week.

Idol took steps this year to make sure its front-runners wouldn't get eliminated early by a fickle public, giving its judges the power to save one ejected contestant and arguably arming Lambert with a lot of onstage good will and production values to keep him in the game.

We'll see tonight whether all that grooming helps Idol avoid Dancing's mistakes.    

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