This was our second cruise on Princess, having just sailed on the Royal a few months ago. It is difficult to not make some comparisons between them. There are some features I really liked on the Ruby such as the true Promenade Deck that you can walk around and the pool at the aft of the ship, neither of which the Royal had. However, the Royal is newer and a bit nicer overall.
Let me break down the high and low points:
Embarkation/ Debarkation: Both processes were easy and flawless. This was the fastest and easiest I have ever gotten onboard a ship. Our luggage was also delivered promptly. Debarking the ship was also easy and we were on our way in no time. Really excellent all around.