I can't decide, especially since I don't listen to either album in their original form anymore. For SFAM, I use my personal mix of the David Bottrill mixes, or the Alternate Mixes from
The Making of Scenes From A Memory. The mix is over-all a bit more pleasing to my ears and I really like the stuff that Kevin Shirley mixed out from some of the songs. I also like having the "Opening Scene" mixed in with "Regression", especially since it opens with the vinyl record that is, on my version, reprised at the end of the album during the scene with the therapist invading Nicholas' home.
As for IAW, I can't not listen to it without "Don't Look Past Me" and "To Live Forever" somewhere in the mix, especially the former, which is a song I think they should have left on the album. With both songs added to the original album, it becomes a 68-minute monster album. Heck, even throw "Eve" in there too, just so the album has an instrumental (since most of their albums had instrumentals anyway), then it becomes a 73-minute, 11-track epic album that matches anything they've ever done.
There's a LOT of great things on both albums, but if I REALLY had to choose, SFAM by a hair. But if I never had to choose in my life, I'd pick both.
-Marc.