I remember frequent comparisons with Oblivion in previews and interviews, but I don't recall if it was the developers or the journalists saying it. Whichever, there was quite a bit of "vs. Oblivion" talk going on, prior to the game's release.

I just checked the box cover. On the back, they quote a number of journalists, and the last quote is, "It's Oblivion on steroids!" - Hardcore Gamer.