Thanks for the replies! So, the Happy Hour is supposed to be nice at the Hilton but food is not, so just a nice view with drinks. I like the idea of some drinks at bar/restaurant in the lobby (?) for Titanium at the Sheraton.

We will either do 1 or 2 nights (very full Japan trip plan!) and the current idea is to do Miyajima and Peace Museum, which would be fine for one day based on past experience. If we add Mazda Museum we could do 2 nights there, but then only one night (or none) at Naoshima. Hmm....Seems the Sheraton has good connectivity.