This guy has the unlucky distinction, I think, of being one of the worst dwarf allies in the game. He has 2 stats per cost, which is typically ok, but they also unfortunately perfectly match the admittedly laughably undercosted Erebor Hammersmith. Compared to similar dwarf allies, there's Longbeard Elder that can scry for you, and if it doesn't wiff commits an extra willpower for free, and Ered Luin Miner that if you happen to not discard, at least is neutral to make up for his 1 less health.

His ability is also too expensive in a cash-strapped sphere, but it definitely has to be, since there is no limit. There's perhaps a time where a 4 player fellowship could boost this guy to ludicrous proportions to pass a quest when you need, but I'd much rather use those lore resources with Erebor Record Keeper to ready a much better dwarf.

This is an amazing card for those scenarios that feature lots of locations with nasty (travel) effects. Don't make the mistake I did in thinking it's a one-off effect: the player stays in control of the card when it's attached to a location (see also section 1.38 of the FAQ). That means that you can decide to use it's Response again at a later time, for example, after having travelled to a location and skipped its effect. The only restriction is the availability of other locations (and the proper use of the Action Windows).

Indeed, this key opens many doors!

There are quite a few cards that reduce cost for in-tribe cards - O Lórien!, King of Dale - to name a couple. I think this one absolutely knocks it out of the park for Creatures, so much so that I hardly use the readying unless I have a really huge Eagles of the Misty Mountains.

Reducing cost by 2 is already fantastic, and not even reducing with a minimum limit of 1 means you can play this and a Loyal Hound or something on turn 1. But I think the key part to highlight is just how good it is to play an Eagle ally 1-2 turns early. Everyone knows tactics is a slow, expensive sphere, and I believe the eagles have the impressive stats they do because of it. Their cost is also high to offset the benefit of their powerful abilities, needing you to hold on until they finally come in to save you (pretty thematic, I guess). Radagast's staff essentially negates these two drawbacks. Misty Mountain Eagles can come into play and start snowballing way earlier. Cards like Meneldor that you want to recur feel way better when that recurring cost is 1.

It is extremely powerful, and ridiculously fun.

I've really come around on this guy, and he's steadily become a go-to in my tactics decks even if I'm not running eagles. Asfaloth is regarded as the king of location control and for good reason, and I would argue that Meneldor comes pretty close, especially in dedicated eagle decks, or in lower player counts where you might not need Asfaloth's 2 progress every turn.

Obviously he is most powerful in a dedicated eagle deck where he can soar in and out, slapping 4 progress as he goes - a key threshold for many locations in the game. Gwaihir can draw and play him for free for a turn. Flight of the Eagles in this AP can give you a beneficial encounter card along with the progress. Obviously I would be remiss not to mention Radagast's Staff that can give you this guy's impressive stats for just 1.

Outside of a standard eagle deck, he's a fantastic questing ally in Tactics, as others have said, and you could include him just for that. Outside of sphere, if Sneak Attack Gandalf feels too broken, this is a great alternative.

Bond of Friendship may be the most powerful individual card in the entirety of the card pool. While there are some very real restrictions, the benefits far outweigh them to the point where against standard quests I can struggle, I can take on the Nightmare version and feel comfortable. In Emmental's review below he covers restrictions quite well, so I won't go through those again. The benefits though are worth expanding upon, because while the extra hero and resource are powerful in and of themselves, there are some nuances I think make interesting discussion points, and also one I'd like to add.

The extra hero and hero action are not just a 33% increase in your output - they offer some interesting extra choices by allowing a hero to shore up the weaknesses of the other three. For example, playing an ally bouncing deck with Lothíriel, Éomer, and Imrahil is a powerful combination, but card draw is an issue long term with all the allies leaving play. Playing the same style of deck with the Bond of Friendship contract allows taking another hero who can help with card draw, essentially eliminating the weakness of the core idea of the deck right from the start and not requiring you to find the card you need to do it from your deck.

Another example to this point is a Hobbit deck - their chief weakness is being able to defend the enemies they want to engage. Tom is answer within the archetype, but if you're taking Tom, one of Sam, Merry, or Pippin normally can't be in the deck. Playing in contract allows you to take the extra hero to shore up the defensive weakness - usually it's Tom and SpMerry using Thorongil to get back to his Tactics version, but you could also use Beregond with the three classic hobbits and keep your threat right where it starts.

Another benefit of the extra hero is with global benefits - More dwarves for Dáin to benefit, starting with 4 dwarves (or 5 if using Bombur) to proc Thorin, or more Dale characters for Brand. It also allows global boosts to have more targets to start with - things like Sword that was Broken or Faramir can be worth playing earlier if you can because they have more targets in play.

The benefit the contract offers that gets overlooked most is the fact that you have access to cards from each sphere, and all that that entails. You don't need to make difficult decisions about which sphere to leave out, and to which element of game play you no longer have access. If the Hero combination you want doesn't have a lore hero, you don't need to give up on healing, scrying, or card draw, or settle for less efficient options. While you can still play those staples using A Good Harvest or the Songs, it requires multiple card combo's, and enough card draw to make it work. In a Bond of Friendship, you just have access to those right from the start.

There are some very powerful staples in each sphere that will always make a deck stronger, or more resilient. Things like Steward of Gondor or Faramir; A Test of Will or The Galadhrim's Greeting; Feint or Gondorian Shield; Gléowine or Warden of Healing. Being able to take all of them, even with the limitation of 2x, is going to make a deck handle a more broad set of situations than you may otherwise.

The 10 card restriction per sphere I've found is actually a really enjoyable part of deck building - I want this card, what have I got in other spheres that can do the same thing? Or which of my other cards in this sphere have replacements in other spheres? The chain reaction of moving cards in and out when deck building is delightfully puzzling, I enjoy building Bond decks as a result.

I'll also leave you with this thought - you can now take Beravor, and still have 3 hero actions without needing to find any readying. The restrictions are enough to stop it from being easy mode, but it's not far off - an extra resource and two extra cards per turn, with access to all four spheres. Insanely strong.