Those IV- cabins with a big- I admit though- a very big window that can be opend, never appealed to me. I refuse to call them balcony cabins. So I choose a SV for the Maiden Voyage of Apex. Wonderful cabin choice- and the only one I would book on board their new class of ships.
Since M Class ships are my favorite and as long as they are around, which might be not for much longer- I stick to them.