Using Skymiles, your choices are either 30k miles for Delta metal, or 35k for United. I've done both, United's schedules are a little better (can fly on them to all the islands, and have nonstops from LAX/SFO to east coast), also I thought their service was slightly better. Reports of the DL 767-400 are not too favorable, either.
Both allow you to have a stopover. I did PHL-SFO-HNL on both United (SFO on way over) and Delta (SFO on way back), and my parents stopped in Las Vegas on the way back from HNL last year.
If you can work with the Delta schedule, I would try to go with them, and save the 5k miles for another trip.
Jeff