I give this a better-than-average rating because of a couple of good things, but there were also some average aspects that you don't expect in top tier restaurants. Above all, it is hard to find a better setting than this - dining on an outdoor patio, right on the beach, with an entertaining sunset every night. Pacific'O is a few blocks south of the old part of Lahaina. Parking in Lahaini is never easy, but there is a (for pay) parking garage which serves this restarant and other establishments. I strongly recommend reservations.
We were seated promptly, and our friendly waiter took our drink orders before too long. The service from start to finish was not speedy, but was better than average. Since there were 8 of us we did not expect (nor need) especially fast service.
Everything on the menu sounded good, usually a good sign. I began with a salad topped with roasted local onions and goat cheese - a good start. My main course was mahi mahi on tagliatelle (a fettuccini-like pasta) with mushrooms. The fish was better than average, but the pasta with mushrooms really made the dish. I tried a bite or two of the chocolate decadence dessert ordered by someone at our table, and it was delicious.
There is a nightly luau at the proprty next door, and there is foot traffic from that, so you shoould ask for seating on the north, or Lahaina, side of the patio. The performers warmed up for the show on the beach out from the restaurant, providing some added entertainment as a bonus.
Overall, a better than average experience, but it was prrobably the most expensive dinner we had during the week, and I did not feel like the value was there. No doubt, part of what we paid for was the location and atmosphere but, for this price, the food and service should be exceptional.