Sorry for the late reply. Snow has been good here but lift delays and mountain closures mean it isn't as awesome as one would expect!
kiroro is FLAT. Really flat. Do not go there if you can go to Rusutsu. Sheraton is probably just as convenient as the Westin in slope access, but I haven't stayed at the westin, only looked at the area.
I really dislikes Kiroro and the snow was poor. Rusutsu is basically full of Niseko people now though, so it will be a little more crowded. Dunno, the choice is clear to me but we aren't the same person!
