I was on PC dining on the Sapphire last December. It was not very well done. I did PC on the Star Princess 3 years ago and it was great. Not now. First, even if you have a reservation, you must wait in the same line as walk-up passengers just looking for a table. This took at least 10 minutes each time we tried. Every table must be input into a computer. If you want to just walk in and go at a prime time like 7:00PM, there was a 45 minute wait every time. In every dining room. So we tried getting reservations. They ONLY took reservations at 6:15PM and 8:00PM. And as I said, you still had to wait with others without reservations. Basically it's just like traditional dining.
They had one PC dining room that opened each night at 8:00PM. So we tried it once thinking that arriving at an empty restaurant would make seating easier. Wrong. Lines were the longest ever. And again every table must be assigned by a computer which is a very slow process.
Next time, I will go traditonal.