Absolutely the best!And as anime it is unbelievable!Both FMA and FMA Brotherhood went beyond my expectations!I believe that for concept,plot,art,characters and most importantly dialogues it gets 10 out of 10!Also i think it belongs to seinen genre because it needs more mature thinking to understand the sub context of the whole concept..Hiromu-sensei really thank you for this masterpiece!!
Fullmetal Alchemist