The guitar sound on Master of Reality,Vol. 4, and Sabatage sounds pretty heavy for the time and even in today where a lot of guitarists can't even acheive decent heavy tone without sounding like they run cheap distortion out of some weak amp. Sabbath are like hippies that actually focused on riffs rythmn and songs instead of sounding like every other wanker band that sounds like they have been tripping on acid for 3 weeks straight. I do not think tony iommi gave a shit about anything else that was going on or wanted to even be some guitar god that can solo until the cows come home, he's just as capable as anyone but chooses to focus on rythmn and structure over lead playing(which is mainly what bands of the 70's,etc focus on). I hate bands that put lead player over everything. Tony focuses on basic chords and achieves alot.