I had an old dry bag for my phone that was fine until the zipper died. This is surprisingly burly and waterproof to 100 feet. The neckstrap works fine I guess but seems a little chincy compared to the quality of the bag.
I just got this Hermetic bag, and went camping last weekend where we crossed streams and it was great to have my iPhone safe and dry. This is a must have for beach, mtn biking, boating, camping etc.