You're going to los San Fermines, by far the wildest most out of control party I've ever experienced. Believe me, it doesn't make a difference if the hotel is great or crap, because you won't be spending much time there other than to drop your bags and stick your head under a shower from time to time. Just be thankful that you found SOMETHING, a huge number of party goers just crash in the park.

As for the "wisdom" of going to Ibiza....were I your liver I'd advise against it, after Pamplona!