I have both recordings also. I remember first hearing the 96 recording directly after it was released in London - my uncle brought home the CD and I was quickly smitten by the story and the music. I heard about how poorly it was doing and that they were gonna tool with the show. 2 years later an apparently better show was in the making - but the reviews in the US led us all to believe otherwise. The newer MG garnered at least some positive reviews, but not nearly the push they were hoping for, thus giving Mr. Mackintosh no real reason to give the NY reviewers a field day.
I assume when you ask about the recordings, you wanna know about the songs themselves. I believe the songs are superior in the original: Louison, Someone, I Will Make You Proud, Bethlehem, etc. Many of the songs are the same musically but with different lyrics. In those cases, I usually prefer the lyrics the' first time. I do like Live With Somebody You Love as far as the 99 recording goes, but that's about it. Arnaud's voice in the '96 recording is also rather irritating, but I think his material is better.
If you can get a copy of the '96 one, I would say do it. If you like the '99 a lot, you will get your money's worth in the '96 - 40 bucks or not.
But I won't live alone in a house of regret.