My wife and I are frequent cruisers (19), with 13 on Princess and the others spread between Royal Carribean (1), Carnival (2) and Celebrity (3). We started with Princess on the Golden and to be fair, that class of ship remains my favourite, although lately we prefer Celebrity.
I won't talk about the ports as they are common to all lines.
Specific Positives about Princess in general: (1)Food is very good ( a notch below Celebrity but above Carnival). (2)Love that they have multiple entertainment theaters (Vista Lounge in the rear and Princess Theater in the front, plus piano bars so you can usually find something you like). (3)Service/Staff is excellent (notwithstanding they have eliminated many positions - no longer have wine stewards in the dining room and you have to go to the bar to get a drink when on deck).
Mini Suite was fine except for the balcony.