I don't actually, but I feel there is less lock-in. It wouldn't be hard to move off.
Also, the risk of S3 pricing changing greatly is constrained by the wide adoption. If DynamoDB failed to become pervasive, it would be relatively easy for Amazon to increase the price to make an underutilized service profitable. OTOH, if DynamoDB does become as popular as S3 your exposure to risk will be much less.
Also, the risk of S3 pricing changing greatly is constrained by the wide adoption. If DynamoDB failed to become pervasive, it would be relatively easy for Amazon to increase the price to make an underutilized service profitable. OTOH, if DynamoDB does become as popular as S3 your exposure to risk will be much less.