Its feel luxury. The JR East E655 series is designed for VIP transportation,and a replacement for the retired royal train. It is also named "Nagomi", for reference.
Royal person(s) in transport
Apart from transporting royal person, the train can still be utilized as group reversed train, which is expensive to book. In other word, you can still get a chance to ride on it, if you are willing to pay a lot.
Your majesty, your trip cancel my train I used to ride.
This is the E655-1 (TR) car, which can only ride by royal person.
Interior of the train....not as luxury as I thought?
Well, to be honest, I think riding (luxury one) highway bus is better than taking the E655 series.
The red eye between Tokyo and Osaka/Kyoto.
Pay ~¥5,000, almost completely private capsule seating, go to sleep or get snacks at rest stops along the way.
The interior of buses like Willer are just as nice as premium seats on liner trains and my experience with buses in Japan is that they ride just as smoothly as the trains do most of the time.