I'll take the 2 discs for quality. I have an 11' home theatre screen. I can really see the difference in quality on it. I would never notice the difference on my 52" LCD.
Encryption has nothing to do with presentation quality.
Three and a half hours of uncompressed 1080p video is about 2000GB. That's a lot of compression to get it down to 50GB, even before you get into accompanying surround sound audio tracks.
This thread is getting a bit frustrating. If you don't understand the technology, don't jump into a technical discussion with "facts" that you're making up as you go. If you can't even tell the difference between DVD and Blu-Ray, why be concerned with the BR release at all? And perhaps most importantly, just because you EXPECT you wouldn't be able to tell the difference between these films compressed to fit one disc and these films compressed to span two discs, that doesn't mean you're right. Those of us who understand the technology know that we can indeed tell the difference. The studio is not holding anything back, and I'm sure they would love to stamp out one disc as printing and packaging a second costs money. Rest assured, they are spreading this across two discs in order to give us a presentation that won't have people bitching at them over it.
Your question was answered several times before you asked it. This entire thread is about compressing the movie to fit onto one disc. That said, not all of my comments were directed at you.