Loved the Pan Pacific luggage service. It can seem a little nerve-racking to hand over your bags, but man when I saw the line to drop off baggage was I glad I got to skip that step! It's super easy, the only thing to note is on the morning of a cruise EVERYONE is using this service, so they often tell you it will take 20-30 minutes after you call for the bellservice to come to your room to pick up your bags. I'd make sure to schedule that extra time into your day - call early enough before you want to leave for your PAT or your room check-out time.
To help with the nerves, I just tried to remember that they handle TONS of cruisers bags for TONS of different cruise lines. If they messed up and didn't get peoples bags onto the ship often, then I would probably hear about it somewhere, and I don't.
You can always drag them down the elevator to the lobby, and then transfer to the elevator that goes to the parking garage/cruise check in yourself. But it really is glorious not to be dragging bags around all morning.