On the Backs of Angels > PMU
I thought the vocals were weak on OTBOA at first, but I've come to love them and they get stuck in your head. I do agree that it's not easily memorable, and that's fine. There's much good in this song and it grows on you, which is a good thing to me.
A lot of PMU similarities (they both have the same guitar prechorus run basically) and this comparison makes sense. The outro is particularly awesome on its own and as a way to end the song (seriously, listen to what each individual is doing, it's subtle and yet it builds to an awesome ending). Some of the interplay between Rudess' cool futuristic riffs and Mangini's snare hits are musically great to listen to.
I think where PMU relies on "Hey! Let us show you the basics of DREAM THEATER PULL ME UNDER IM NOT AFRAID," OTBOA says "You know the drill, but we got some new players and some cool extras PMU doesn't have...mind you, JLB can't sing as high, but he's doing fine."