my opinion is quite clear. Its a great overpowered card. Extremely useful in control decks.
If you criticize it alone, yes its overcosted (not only this, any card with 6cc), and its vulnerable to instants and sorceries.
So, the only environment I could imagine it, in an artifact deck (not Stax), with only creatures 4 Metalworkers, dual-mana lands like Ancient Tomb & City of Traitors, and why not Locus lands. 8 of them, Cloudpost and Glimmerpost. Especially Cloudpost can easily transformed into Mishra's Workshop.
Spell control with Chalice of the Void, Trinishpere, and Null Brooch, and creature control with Ensnaring Bridge
For win condition... Helm of the Obedience / Leyline of the Void.