Just to give a second corroborative opinion I spent 5 weeks in the Century Hyatt last year, staying on the Gold Passport floors. (free coffee and pastries in the floor looby each morning) A good room, with excellent view of Mt Fuji. See how many origami swans you can collect. The earthquakes were an almost weekly event.

The hotel is a 10 mins walk from Shinjuku station through a walkway, or 5 mins by another underground passage from Nishi-Shinjuku which is a smaller subway stop. Do go and have a drink in the New York Grill at the Park Hyatt if you can afford to, the journey up through the tower is an experience, and I managed to lose a few colleagues en-route one drunken night.

If going by coach from Narita take either the one marked for Century Hyatt or the one for Hilton (as the H is just across the street). For food, email me, and i'll take a look back through my expense claims. I'm jealous.