I've never understood the camp that loves Part 1 by itself. Like, it's nine minutes long, and 5 1/2 of that is basically just an overture--plus one of the non-overture sections in Part 1 comes back in Part 2. I can understand why some would say Part 1 > Part 2 (The Reckoning is the worst section of music on the album overall), but Part 1 over the song as a whole, or album as a whole? To me, that's like saying that the overtures on SFAM or SDOIT are the biggest highlights. They're all good pieces of music, but they sound woefully incomplete by themselves, and thus it's hard for me to consider them superior to other quality songs.
ITPOE as a whole for me, just barely edging out TMOLS. ITPOE has 20 killer minutes and 5 bad; TMOLS has 15 killer and 0 bad. Toss-up really, but ITPOE has slightly higher highs, I guess.