I thought I'd dive into this discussion.
LuPone was never going to be in the film version -- too old for it by the time Evita was going to be made into a movie. As well, her voice would just overpower a cinema house. She's trained for the stage, not for the cinema. One more point: her portrayal of Eva Peron is as Tim Rice and Andrew Lloyd Webber would have liked the character to be: cold, arrogant bitch-queen.
The film version was going for a character much warmer and multi-faceted (and closer to what Argentines see their Evita to be). I thought Madonna delivered a magnificent performance: charismatic, alluring and complicated. I by no means think Madonna is a good actress, but I think she really pulled it off in this movie (and worked damn hard at it, from what I've read). Question: do people on this board criticize Madonna's performance because she didn't deliver a convincing performance, or because she's Madonna and not a big Broadway star?
One more thing: unlike Moulin Rouge and Chicago that followed, the emphasis Evita the movie was NOT that it was a musical, but that it was a biopic about Eva Peron. So whether Madonna sang the score in its original key in inconsequential to me: she delivered a believable and identifiable Eva Peron, which is most important.
BlueWizard's blog: The Rambling Corner
HEDWIG: "The road is my home. In reflecting upon the people whom I have come upon in my travels, I cannot help but think of the people who have come upon me."