The concierge cabins are 173 sq ft plus 43 sq ft balcony. Smallest cabin on Paul Gauguin is 202 sq ft and smallest on Mariner is 252 sq ft plus 49 sq ft balcony. The Penthouse Suites on Oceania are 260 sq ft plus 62 sq ft balcony or just a bit larger than Mariner. (I used Nautica for all cabin sizes since these are sister ships.) Of course, smallest on Voyager is 301 sq ft plus 55 sq ft balcony.
My comment on water and cokes is not the cost nor the signing of chits; it is the ready availability. On Regent, I can find cokes and water in computer room, card room, or even unmanned bars. I can always find plenty in the refrigerator in our room. If I am in someone elses room, it is no big deal for me to "borrow" one of theirs since there isn't a charge involved. This may seem minor but when you are wandering around a ship all day, it is nice to always have liquid refreshment on hand. Working on a jigsaw puzzle or surfing the net (for free) or just reading a book in the library can create a desire for a cold drink. I have just gotten used to Regent.