My thoughts:
Coin of the Realm: Pretty handy. I will probably want one or two in my deck. It's nice when your terminals collides.
Guide: Awesome! Who doesn't love skipping crap hands
Duplicate: This is pretty cool. And, no, it doesn't have to miss your reshuffle since you can call it the turn you play it. The ability to gain six costs is pretty good. Smugglers does it, but man, if your opponent is going for a different strategy than you, bah humbug.
Transmogrify: The thought of upgrading a Fortress to a $5 cost makes me salivate.
Anyway, the cards in Adventures seem really well designed. This set seems very solid. Also, reserve cards add a lot more strategy to the game. Now, you have to think of when to call your card and then you have to think that if you don't call your card at a certain point then it will miss the shuffle. This seems to add even more decision making than coin tokens, I think.