These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Broken Base: Hoo boy. You've got your Joey Belladonna fans, your John Bush fans, the occasional lonely Neil Turbin fan...Dan Nelson is by and large left out of the discussion, however, as he never released any recorded material with the band and thus hardly anyone actually heard him.
A subsect of fans in the early 80s metal/thrash scene hated the "maturing" of the their sound after Fistfull of Metal, which along with replacing Turbin, added more melody and slowed down from the 100 bpm all the time style. Granted, nearly every band of this era moved on similarly (Metallica, Megadeth, and even Slayer to a degree) and received similar accusations of selling out at the time from the hardcore speed metal faithfull.
Take a Third Option: Some people think their 80s material was better when John Bush did the vocals. These fans were lucky to receive not only the live album Music of Mass Destruction but the studio album The Greater of Two Evils, a re-recording of their biggest songs with their 2004 line-up.
Ear Worm: Practically every song on Worship Music.
Face of the Band: Despite being the rhythm guitarist, Scott Ian is considered this due to his being the only member of the band who has been with them for their entire tenure and also largely due to his appearance in various VH-1 commentary shows.
Casual rock and metal fans can typically name Scott Ian first as a member of Anthrax. His Face of the Band status is probably reinforced by him singing lead vocals on the band's Breakaway Pop Hit, and biggest commercial hit to date, "Bring The Noise".
It's Popular, Now It Sucks/They Changed It, Now It Sucks: They got this treatment and were accused of "selling out" when they chose John Bush as their new lead singer and with their more mainstream sounding album Sounds of White Noise. The band's rhythm guitarist, Scott Ian commented on this in an interview saying, "The bottom line is, everyone in this business is in it to make money. Myself included."