We're D+ on RCI, and have some Celebrity and Carnival. The main thing I wish I had known was about Princess Balcony cabins (at least on the ships we've been on). The possible balcony categories are Balcony, Deluxe and Premium. Only the Premiums have any extra seating, a loveseat, the Regular balcony and Deluxe only have the hard desk chair. I had no idea that was a question I needed to ask. That might not be a big deal to some, but we need a place to sit.