I may not do the Aerosmith catalogue in full as planned if Toys In The Attic and Rocks aren't strong albums. Since I was lukewarm on ZZ Top's Eliminator you have probably noticed that's the only ZZ Top album I've done.
I'm not an audiophile and have never really noticed when one CD's mix is better than another with the exception of Rush's Vapor Trails. This is not counting stuff like the Iggy mix vs. Bowie mix of Raw Power.
I'm also not an expert on what constitutes "good vocals" from aging heavy metal frontmen--I've seen comments on some of Ozzy's post-Parkinson's performances that people are stunned he's still able to do as well as he does at all, and people seem to LOVE later performances of "Painkiller" by Judas Priest where Rob Halford has to bend down all the way to his knees to sing it and even then still seems to be missing notes, but what do I know.