This was our first cruise on RC and a big ship like the Harmony of the Seas and have quite a few tips that I think would be beneficial to others(in no particular order):
1. MyTime Dinning doesn't really work for a party of six unless you are Ok with eating very early (at or before 6pm) or later (8pm on). The "prime" dinning time of 6:30pm-8pm was taken for every day the minute we arrived on the ship. Book a good time in advance.
2. Show times will impact your dinning time but the show times are not announced before you cruise. We suggest picking the same dinning time every day in the prime time slot as soon as you are able to make dinner reservations online prior to the cruise and then you can move your time to a less prime time to accommodate shows. If you are traveling with kids, the shows you will want to go to are generally 7:30 or 8:30pm start time.
Good enough for us as we did not large amounts of time in the room.
Terrible stop - we originally were not going to get off the boat but did so anyway to just walk around the shopping area, which was way too touristy and dirty. The stop was way too short so the excursions were too quick and the one we really wanted (Atlantis water park) was ridiculously expensive.