This was my 12th cruise with RCC and everything went better than expected. I booked in November and truly believe Nov-Dec is the lowest cost time to cruise (especially on this ship).
This ship is very well organized (it has to be to support the 6000 weekly visitors). I read a lot of reviews on CC regarding the food and main dining room . The food on all of the 6 RCC ships I have been on is the same. The main difference for the Oasis is the addition of the Park Café, Wipeout Café, Johnny Rockets Breakfast, Bisto Cafe (Adult Solarium). These are great additions and kept me free from joining the Windjammer mass buffet. If you spend another 70 dollars pp for the specialty restaurants you may find less people, but I do not see the food being that much better. I found the MDR to be less than full with excellent service and food. If you have an issue - move to another table. There were plenty of open seats.
There has been a change with the Crown and Anchor setup. No more coupons - benefits are electronically on your Seapass card. It's up to you to ask for the discounts. FYI - there are 7 million Crown and Anchor members now. I can see that in the future the number of "diamond" members could be too large to support. RCC has nightly happy hour parties (5-8:30 pm) that keep me Loyal to Royal for diamond members.