I never saw either performer, but I have listened to both and much prefer Glenn Close. Though Lupone is good, she just wasn't right for the role of Norma Desmond. She doesn't put much passion into the songs, and not for a moment do you believe you are not listening to Patti Lupone. Close acted the role so well, and though her voice wasn't amazing, it was well fit for the show, because you really felt like you were hearing Norma Desmond, because of how much Close put into the role. Lupone just didn't do that.
And don't blame ALW too much for getting rid of Lupone. From what I have read, Paramount, one of the major backers of the show, put a lot of pressure on ALW to cancel Lupone's contract. From what I've heard, he initially refused but then caved into the pressure from Paramount. So even if you are a Lupone fan, it was Paramount that was smoking the crack.
Keep your morals, I don't have time. Keep your lovers, I'm changing mine!
-The Likes of Us