TL;DR: This is 100% a "build-around" card, but if you do build around it, it's incredible.

I usually don't like temporary stat-boosting cards unless they have the potential to make a big impact. Scouting Party is that 100%, but it isn't something that you can just throw into any deck - you really have to build around it, which is why I never used it at first. But it so happened that one day I noticed that I had two Scout heroes in my collection that I hadn't used yet (Idraen and Lanwyn), so I decided to make a Scout deck and give it a go. (Edit: You can find the deck here.)

While building this deck, I kept thinking that this card is more restrictive than it looks! It turns out that out of a lot of the questing allies that I usually like to use, such as West Road Traveller, aren't actually Scouts. But I took this as an opportunity to dig even further into my collection and pull out things like Sailor of Lune and Mirkwood Explorer that I also rarely use or have never used before.

The first quests I played with this deck were The Caves of Nibin-dûm and the first two Dream-chaser quests in a 2-player fellowship. And every time Scouting Party came up in the game, it made a HUGE impact - it ended up boosting my by 10 or more every time I played it! It's balanced pretty well - it's restrictive to play it, but if you build your deck around it, it's incredible.

However, like most other temporary stat-boosting events, there were a lot of times where my stats were already good enough that I simply didn't feel like I needed it. Though to be fair, the other deck in the fellowship was playing Prince Imrahil with A Very Good Tale and Captain's Wisdom and was spewing out allies left and right, so that might not be this card's problem, lol.

Also one thing to note: This card is obviously best when you go as all-in as possible with your questing. This is not a bad thing, but this factor alone makes the card much better in multiplayer than in solo, because then you can go all-in with your questing while the other players handle the combat. One of the reasons that made me not use this card for a while was the fact that I play true solo about 60% of the time.