Good choice. Much nicer than the Grand. Aurora is closer to Red Square and Aeroplate (if walking) and personnally I think it has a better "american breakfast". They definitely put on the charm for all guests and make you feel appreciated as a loyal customer.
I'm currently staying at the Royal Aurora and they definitely recognize platinum status - executive lounge access, free internet and breakfast. The staff has been very friendly and accomodating. I don't think you'll go wrong.