First off you don't have to be a jack^ss while arguing your side of this. With that aside...
I strongly disagree with the Coner Oberst sounding different, and yes i have listened to almost everything they have both put out. I do not like Elliot Smith but i still have his first album from 1994 up till his recent 2007 release.
And yes Conor Oberst did come before him... His solo album was released a year before Elliot Smiths in 1993. (Water)
Example:
YouTube - Elliott Smith - Whatever ( Folk Song in C ) LIVE < Elliot Smith
YouTube - Conor Oberst - Hubcap < Conor Oberst
Sounds very similar to me, and thats one of many examples. yes difference in singing, with more screaming aggression coming from Oberst. But nothing you couldn't say as a difference between bands such as Chevelle and Stained.
Edit: And to be honest, you obviously do not give bands such as Chevelle an even remotly fair chance before judging them right off the bat.