For real though, my opinion is actually Mindcrime > Seven Keys > Seventh Son > Justice
Also out of curiosity, I looked up what RYM's top 10 metal albums of '88 were (to see if there were any we forgot), & here are the results there:
#1. Metallica - ...& Justice For All
#2. Iron Maiden - Seventh Son Of A Seventh Son
#3. Slayer - South Of Heaven
#4. Queensryche - Operation: Mindcrime
#5. Bathory - Blood Fire Death
#6. Helloween - Keeper Of The Seven Keys Part 2
#7. Death - Leprosy
#8. Voivod - Dimension Hatross
#9. Testament - The New Order
10. Riot - Thundersteel
(11. Crimson Glory - Transcendence)
I haven't heard any of these apart from the 4 mentioned above, but to anyone who has, are any of these worthy competitors too?