"Master of the forge reads, "Action: Exhaust Master of the Forge to search the top 5 cards of your deck for any 1 attachment and add it to your hand. Shuffle the other cards back into your deck."

This strikes me as an odd phrasing. Does this mean that you get to look through the top 5 cards of your deck and if there are any attachments, you can add 1 to your hand? Or does it mean that you can search for 1 specific attachment (Forest Snare, Burning Brand, etc.) if it is in the top 5 cards you can add it to your hand?

I see what you're saying, but here's RR Search :

Quote

When a player is instructed to search for a card, the player is permitted to look at each of the cards in the searched area.

If the player finds a card that meets the eligibility requirements being searched for, the player may add that card to the game area indicated by the instructions on the search effect.

So, you look at each of your top 5 cards. The "eligibility requirement" is "any 1 attachment". So you add any 1 attachment you find to your hand—you do not have to name it in advance.

It is a bonkers good card!

Especially in decks that are heavy on the attachments, like Trap decks. You can also double their efficiency in multiplayer through using Leather Boots to ready them almost every round (when a location is revealed from the encounter deck).

The deck doesn't even have to be very heavy on attachments but also if you depend on getting that one key attachment (looking at you Vilya).
Master of the Forge just makes a lot of decks way more consistent.

But @Durins_Father is of course 100% right the more attachments the better for MoF.

He's also useful in conjunction with Imladris Stargazer to shuffle up a poorly stacked deck.