I had a hard time getting past the visual style of Morrowind and it's environment. Was way too swampy and wasteland-like for my tastes. Oblivion was definitely gorgeous looking, obviously being newer, but even if those rolling hills and grassy fiends were done in Morrowind's engine, I'd still find it more welcoming. I think like everyone else, it comes down to whatever sets off a red flag in the back of your mind about initial presentation.