If you read some of the comments on biddingfortravel.com, the general consensus is that Priceline is not a good way to buy Hawaii tickets, because there isn't enough of a discount (if any) to justify the inconvenience.
Also - you will not get a ticket during a popular time of day to fly - it will be very early morning or a red eye. Those flights are less popular, so that's what the airlines give to Priceline. Because of this, I don't use Priceline for airfare. I want to control my route and departure times.