I like Island Hermit. Being able to scout out 2 cards you have prized is useful, and then you get to draw 2 cards from your deck to sweeten the deal. Island Hermit is most useful in decks like Kricketune, where it is essential that you know if you have Kricketot/Tune prized, as having a Kricketot prized can very well cost you the game. By being able to scout out 2 of your Prize cards, you can either find it or at least eliminate what 2 aren't Kricketot.
Modified - 8/10 (Useful effect, but many people will prefer more cards from their Supporter, like TV Reporter or Steven's Advice)
Limited - 10/10 (You get 2 free cards and scout out half of what you have prized, and as you may only run 1 particular card you need, this can find it if it's Prized)
Unlimited - 1/10 (No need for this, quantity > effect here)