No Prayer For The Dying is very okay if you just want to hear some corny rock riffs mixed with some very memorable solos. I think it's one of those fun albums, no one's really into that around here though.
Still it comes nowhere NEAR 7th son, and considering they were consecutive albums, I can understand the backlash.
Fear of the Dark was absolute CRAP though. I think people prefer it to NPFTD because of the title track, because people go apeshit over Maiden songs that are 7+ minutes. Used to be my favorite though, so also unerstandable. NPFTD didn't really have that quality to it.
But Killers didn't have one either, and people love that... The grittiness probably.
Eh I can go on talkin about Maiden for days on end, somebody might need to strangle me eventually.