Of course, Elton John wasn't the only person to perform this number. In 1978, William Shatner sang "Rocket Man" at the 1978 Science Fiction Awards. He doesn't really sing, nor does he play piano. He is, however, accompanied by two other version of himself. (You really can't make this stuff up.) Here's Shatner's... abstract performance.
So, who does it better? A very good question.
Musicality: Elton sings and accompanies himself. Both his vocals and his piano are utterly superb. Shatner isn't really singing at all. Instead, he's doing some sort of dramatic reading. Bizarre? Yes. Musical? Definitely not.
Winner: EltonArtistic-ness: While his music is divine, Elton's performance is a bit lacking. He's rocking the plaid jacket, over-sized shirt collar, and huge sunglasses, but that's about it. Shatner's spending all his energy developing a mood. From the hammy acting to the cigarette to the third Shatner's undone bow tie, Shatner's performance is all about ambiance. While Elton merely sings his song, Shatner gives us a surreal (and extremely schizophrenic) profile of the rocket man.
Winner: ShatnerWhile Shatner's interpretation is clearly more inspired, Elton has him beat in musicality. While this is technically a tie, I'm giving the victory to Elton John. While it is true that pure music transcends spectacle, I've made this verdict mostly because Shatner's artistic interpretation freaks me out. (One Captain Kirk is more than enough for me.)
Overall Winner: Elton (Because William Shatner can be a little scary.)