From what i've heard, it seems less than their best. I was completely blown away by Death Cult Armageddon, the epic scope, and the death/thrash-like elements of the faster songs. In Sorte Diaboli seems less inventive, the songs sounds the same at first listen, and the vocals aren't that great. there are no standout moments like Vredysbyrd, Blessings upon the Throne of Tyranny, or Insight & the Catharsis. The album stays at roughly the same pace throughout. vortex's vocals are great, but they are never used enough (and his lines are always either meaningless or don't match the emotion he's singing with).
BTW Reinkaos had two, maybe three REALLY good melo-death songs, and the rest sucked.