I accepted a URComped "Short Notice Sailing" on Mariner of the Seas; a 4-day Bahamas cruise. I've cruised twice before, both on comp casino offers -- last year with NCL and the year before with Princess. I thought Royal Caribbean's food was as good as or better than the other two lines -- RCI had the best breakfasts for sure, and I was very happy with the main dining room. (The other two lines had way better desserts, though!)
If you care about craft beer as I do, there wasn't a lot available, although Mariner did offer Stone IPA at the Barnacle and Barrel bar, so that was nice. Other bars had nothing that impressed me -- NCL has my vote for that, although I know there are some specialty venues on some ships of other lines.
The casino on Mariner is smaller than some, but I liked how table games are a bit separated from slots, and they did have some of my favorite machines. Slots seemed a bit looser than typical for cruise casinos; maybe it was just my experience, but I actually covered my airfare and ship gratuities with winnings (a few smaller hits and one decent jackpot near the end of the cruise - not a hand pay but close).
There was a glitch in communication and the onboard casino did not have records of me at first - but the onboard casino host communicated with Craig and Stephanie from URComped and everything was sorted by day two so I could get my drink sticker and other benefits. It did shorten my gambling time, though (it was only a 4-day cruise to start with, and I didn't play at all the first day and a half while waiting for access to my onboard account) so I didn't end up playing as much as I wanted to and didn't hit the higher level on the player's club. But thanks to Craig and Stephanie for their extra efforts!