SFAM definitely has some amazing vocals moments, but some of it is also quite plain to me.
He delivers great emotion with some of his best vibrato in Through Her Eyes. He gives some of his best growly vocals in Beyond This Life ("she wanted love forever........ OH YEAH YEAHHHH"). And all of the vocals in Strange Deva Vu are pretty cool, such as the high harmonies you mentioned.
But I find his lyrical delivery in Fatal Tragedy, and The Spirit Carries On to be completely flat, along with a lot of other sections of songs.
Definitely a mixed bag for me. Some moments are really impressive, some parts are just.... there. If the whole album had the consistency of his best moments on the album, it would definitely be among his best. As it is, it's 50% awesome, 50% average (imo obviously).
On a side note, I actually thought JLB had a cold the first time I heard SFAM. Looking back, I'm not sure why.