Naturally, a big reason for this is the Power Nine themselves, six of which are powerful artifacts that speed up your games tremendously
It just so happens that a soldier typal build is the perfect place for this tech
Because the ability includes a targeting clause, its not a mana ability, so you can respond to it on the stack and sacrifice the Engine to something like an Ashnod's Altar, which then goes infinite with Corpse Dance
Ive also found that bringing it up to around 3 or 4 power tends to make it too hard for people to pay the tax when Im playing my Heliod, Sun-Crowned deck
It has made some waves in Legacy as a powerful planeswalker, as all the modes are solid
Fervor also has another foil printing, Core set 2013, which means its appeal is mostly due to its value as a piece of a full set of 7th foils