Embarkation: I have no complaints about our boarding process. It went smoothly and relatively quickly considering we arrived very early.
Public Rooms: I think the only complaint I have (and not much of one)is that I did not like walking through the casino if you were on that floor. The promenade was very nice. Although I prefer the large atriums that Carnival offers on the larger ships.
I think the Mariner could improve outdoor table seating around the pool areas. During the one midnight buffet on deck, everyone was standing around with plates and drinks trying to figure out how to eat without spilling everything.