Next Question:
What is the absolute minimum you require to try and put together an engine?
On Burning Skulls "how to base dominion" youtube series, he succeeded in making an engine every time, even when the components were weak.
Is there some threshold where you think "this isn't worth it"? Like, do you look at a board with a village and a +2 cards component and think "that's enough"? If the village doesn't even give you a card, and the best you can do is maintain a hand of 5 cards, is it worth the attempt? Had a game with festival/steward and wasn't able to make my deck do much.
Bonus: On the occasions you decline the engine, what's the next best thing to look for?
Depends on the payload. You don't play a Hamlet/Oracle engine for Gold payload, but you might for Highway payload.
Hamlet/Oracle isn't even an engine. The only thing it does is sift.
Festival/Steward at least gives you $. But it's basically a clunky Grand Market for $8, which is a pretty bad deal.
I'd say that in general BM is the main thing competing with an engine. So if there's a terrible engine, but a strong BM enabler (Wharf, Embassy, Margrave, Council Room, Hunting Grounds, maybe Catacombs and Pooka) you should probably go for that instead.