At the moment I am writing this from the Ritz Carlton Mandapa in Ubud.. Extraordinarily nice and well worth consideration (our room pool is bigger than some hotel pools I've seen). Staff can't do enough for you.
In a couple of days we are moving to Amankila. It will be an interesting comparison.
BTW, regarding the rainy season issue, I understand that during December and January this year there was very little rain. We've had sunny mornings each day, the afternoons partly cloudy and a couple of days with rain for an hour or so. It's been perfect (and less crowded with tourists).