If you stay at the Royal Park, I recommend asking for the side facing the Ferris Wheel. I think it is a nice view at night.

Watch out for the "non-smoking upgrade" that this hotel tries to use. Some other hotels in Japan do this also. If you request a non-smoking room during reservation, they will often say to you at check-in that they only have smoking rooms left for the type of room you booked, but you can pay for a more expensive room that is non-smoking. If you argue long enough, they usually magically "find" a non-smoking room for you.