On a purely 'potency' discussion, JBJ's voice is certainly not what it was twelve years ago. He obviously struggles with high notes at times, and he'll occasionaly get nasally live (something that I firmly believe is linked to his smoking, which is why it wasn't an issue on the HAND tour). His vocal chords have seen a lot of miles.

With that said, do I prefer JBJ's voice to 90% of everything else out there? Absolutely. Does he still put out very impressive vocal performances live? Yes. There's no doubt his voice improved over the past 5 years, and even songs he struggled with on the HAND tour (Dry County and KTF) got progressively better as they kept playing them. And all the gigs for Lost Highway so far, he's sounded fantastic.

So in short, I think JBJ still has a stellar voice. Is it as potent as it was during the 90's? No. But he's made up for it by being versatile. The long note at the end of MAM or the acoustic renditions of Prayer show where he can compensate for not being able to burst into falsettos.

Of course, the fact he was dumb enough to start smoking is a big blotch.