Although I've been on about fifteen cruises---usually in the ten-to-seventeen-night range on HAL and Silversea---this was only my second Princess cruise. The first, also a four-night California Coastal, was on the Crown Princess (basically, identical to the Ruby) in January of 2015.
I'm married, but I sailed "solo" (my wife has no interest in large ships). As I did on the Crown, I booked an inside cabin, which was perfectly adequate for one person (and probably for two, at least on short cruises).
On the Crown cruise, I had dinner the final night in Sabatini's, which I felt was head-and-shoulders above the main dining room in terms of food, service, and ambiance, and well worth the $25 surcharge. As a result, on this cruise I dined at Sabatini's three nights and at the Crown Steakhouse (the other extra-price restaurant) the fourth night. Both were superb, but I give Sabatini's a slight edge, if only because I prefer Italian cuisine to steakhouse fare.