I have been a fan since IAW was first released. Followed every up and down.
Octavarium is DT's greatest achievement...bar none. To this day, when I am in a DT mood, I reach for 8V as an ultimate start to finish DT listening experience even before I will reach for IAW, Awake, SFAM or SDOIT.
DT12 is fantastic, and the best album they've released since 8V...but I don't think they will ever top 8V.