Are you talking about the songs "One-Winged Angel" and "Advent: One-Winged Angel"? In game, I prefer the FFVII version, but as stand-alone listening, it's a tough choice since I've got so used to the original version, but the AC version is great too, especially the Live version of A:OWA, which was played in the FF More Friends Concert. KH's arrangement is also very good, although it pretty much has the non-choral parts removed.