David Zurawik from The Baltimore Sun has made (on the 15th of May 2009, just discovered by me…) an interesting analysis of the phenomenon of Adam Lambert vs. Kris Allen, comparing their individual appeals.
Zurawik claims that each of them represents ‘an archetype of musical and sexual identity at least as old as television’.

Elvis Presley vs. Ricky Nelson

The icon of that era from which Lambert descends is, of course, Elvis Presley. (…) He was either being kept off network TV altogether – or shown only from the waist up because of the nasty things censors thought his hips were saying to teen girls.
It goes without saying that Presley was a sex symbol, but the difference between him and Ricky Nelson matters – just as it does with Allen and Lambert. Presley was non-parentally approved, bad-boy sex in the backseat of a hot car parked down by the deep, dark river with lots of pelvis-to-pelvis grinding in the midnight hour.

And after this comparison, the author continues to analyse Adam Lambert, comparing him to Jagger, Bowie, Elvis, Prince, Steve Tyler….

Transgression and falsetto

Lambert’s best performances embody that sense of transgression. (…)
And this is where things get most interesting with Lambert. After the sexual revolution of the 1960s, there was hardly an aspect of heterosexual behavior or identity that was widely considered to be transgressive any more. But then came androgyny with Jagger, glitter and glam with Bowie — and whatever with Prince.
Lambert channels all of that, and it is at the heart of what makes him so dynamic to watch onstage. He is a self-contained drama of identity reminiscent of the great Japanese actresses who with each pass of their hand-fans would assume a dramatically different identity.
In the middle of sounding exactly like Steven Tyler on an Aerosmith song, he’ll suddenly soar into a falsetto scream somewhere up in the Holy Land of Patti LaBelle — and he’ll stand there looking contemptuously like he could hold the note forever if he wanted to.