I read a review by someone who had the Tokyopop versions and they said omnibus one covers volume 1-2 and the first half of 3. Then omnibus 2 covers the second half of 3 and volume 4-5. They've just split it in half essentially.
I have both omnibuses and they're the same size so I'd say this is right. Hope this helps
Ah, that's interesting to know they did it with Tokyo Babylon too. It doesn't affect the flow of reading or anything for Angelic Layer. It was an appropriate place to stop in my opinion.
Might be quite annoying if you're looking to fill the gaps though Rena :/ if you think about just buying the omnibuses instead I agree with Rosencrantz, the paper quality is good and I heard in the same review I mentioned before that the translation was an improvement.