Background: I've been on about 10 cruises. My girlfriend and I did roughly the same itinerary on the Carnival Imagination roughly 9 months ago.
Embarcation: Super fast and unobtrusive. We got there a bit late, but we were on the ship surprisingly quickly. They did however, search my bag in great detail. No idea what they're looking for. They are also ultra-vigilant about intercept booze and making sure you pay the corkage fee on wine over 1 per person. Still, $15 per bottle isn't bad and the sticker they place on your wine allows you to consume it in the dining room with further corkage fee.
Food: Much better than Carnival. We ate in the main dining room twice and the Crown Grill speciality room once. Food was uniformly good to excellent. Ingredients were super fresh. Food was generally of a very good quality and 95% was cooked perfectly. While we enjoyed some of the dishes on Carnival, quality was way, way lower with people sending back dishes and complaining like crazy. Also, Carnival put together crazy ingredients that didn't work to the point that we asked if the cook was on crack. None of this on Princess. Food and service terrific in Crown Grille. Wonderful scallops, shrimp, small but yummy lobster tails, a super tender 8 oz filet mignon (yum), great service, dark wood and dim lighting. Worth spending $25 per person at least one night during your cruise, but reserve early, as it sells out.
Clean, comfortable, slightly dated, great location. Very quiet location. Had issues with the plumbing though.