I've stayed in a 1A before with the portholes. They are just slightly smaller as has been said. I probably wouldn't intentionally book a porthole again. That's just me though, I didn't care for the bumpy ride. For a single cruiser the 1A's are the way to go. There is a chance if you book it as a guarantee you could be bumped to a 4A. I doubt single cruisers would be the first in line for this though.