I'm still completely at a loss as to how anyone could find the original more ambiguous than Vanilla Sky, thus "better." Unless maybe you were watching without the subtitles on.

I saw Open Your Eyes first, and there was scarcely anything explained in Vanilla Sky that wasn't painfully obvious in Open Your Eyes. Crowe also explains on the commentary how he can see 3 other valid interpretations of the movie aside from the most obvious one explained in the elevator. Just because a character tells you something in a movie doesn't necessarily mean there's no ambiguity, especially in a story like this.
And I thought the pop culture reference stuff was brilliant. It gets more to the questions of reality and what makes a "life" in modern culture.
They're VERY similar movies, but, with just a few additions, Vanilla Sky improves upon what's essentially a very clever, well-done sci-fi mystery and makes it an exploration of love, mortality, and consumer culture.