Well I finally played someone who used a Fel Reaver. It was a warlock, while I was in my spelldeck druid (basically a deck I built to finish up the cast 40 spells daily). I felt bad for him, since he didn't even know what hit him. It was even bad even if he wasn't playing my spelldeck, because I had the coin and still had not used it. Anyway, come turn 5 he pulls out the Reaver, and I just couldn't believe it. I had been saving some cards (specifically I had both of my Innervates (+2 mana for turn), as I wanted to play Ysera, but changed my mind since I realized I could dump his entire deck. So I played both innervates, and the coin (giving me 10 mana total), played a wraith (doing 1 damage and drawing a card, getting my big game hunter, which almost made me change my plan), used both my moonfires on his reaver, used my second wraith (again 1 damage, drew a savage roar), used both my claws, used a savage roar, used a savagery against the reaver (killing it), and attacked his hero for 6 damage. In total, I used 10 cards that round, draining his entire deck, killed the reaver, did 6 damage to his hero, and still had 2 cards in my hand (Yersa and the big game hunter). He quit.
Moral of the story, never play a fel reaver without silencing it, unless you are already out of cards in your deck.