I disagree. Not about Heaven and Hell, but I thought he did a fantastic job on Stargazer. Vocally, I enjoy it just as much as the original. And musically, I enjoy the cover better.
He was more stylistically in line with the original on Stargazer, but after listening to the original, this cover leaves you empty. In order to cover one of the greatest rock/metal singers of all time, you have to be in that upper echelon. Unfortunately that is what is lacking here.
Leaves
you empty, maybe. Certainly not me, and I think LaBrie is a better singer than many metal legends. Bruce Dickinson included. Now, Bruce is a better front man, and has much better stage presence and knows how to rile up the crowd. But as a singer, JLB is much more crafted, IMO. Dickinson just screams out half his lines, and it's nice and theatrical, but he just throws technique out the window half the time, I find.
The verses are heavily centered around the B4 (and go higher), which is moderately high when you need to keep it up for a whole verse at a time. We know JLB can sing much higher (and well), but it's all about pacing/phrasing.
Well, I can sing H&H without too much trouble, and I'm definitely not up to JLB's range.
Either way, I think the issue was in HOW he performed it, not so much in whether he had a hard time with it or not. It is the kind of song that needs heart put into it for it to sound effective, and he sounded like he just autopiloted through it, and that's where I think it failed.