I switched from the Westin to the PH some years back when a management change at the Westin made them decide not to give us corporate rates. For me, the quality of the hotel I stay in is a critical part of a business trip. This may not be true for you.

The Westin is a true first class hotel -- service is very good, as in all first class hotels in Japan, but in addition the rooms are quite large by Japanese standards. If you do not routinely demand the very best from a hotel, you will be very happy there.

The PH is a true luxury hotel. The standard room is larger than at the Westin (although there is a lower grade room that is about the same size), the fittings are better quality, the amenities are better. But the biggest difference is in the service which is not just very good, but impeccable.

Of course, location may matter to you, so consider if you prefer Ebisu over Shinjuku or vice versa. But beyond that, realize that as you approach the pinnacle in any category of good or service, the amount of additional quality you get for each additional dollar of cost tends to be less than it was for the last dollar. That's just the way it works at the top. So unless you really feel there is value for you in the additional cost of the PH over the Westin, stay at the Westin -- and don't fret over it, either!