I happen to really like No Prayer, I'd say it's their most underrated album. Of course it doesn't beat any of the 80's albums and it has some big flaws, but I still enjoy most of it. When I was first getting into Maiden, it was one of my favorite albums; I listened to it all the time. Nowadays it's definitely not my go to album when I want to hear Iron Maiden, but I still like it.
Can't stand FOTD, on the other hand. The only song I really like is ATSS and after that it gets worse with each song (with a slight bump in quality in the title track). It's the only Maiden album that feels like a chore to listen to for me. Everything else I can listen to and enjoy quite a bit.