I sent Quintessentially an email through their website, enquiring about their services.
To my surprise, the email was answered promptly and in a very professionnal manner, I might add. They gave me detailed information on their 3 types of membership.

I sent them a long email last night, stating what kind of service I am looking for. The email was answered first thing this morning mentioning that they were gonna give me a detailed answer later on today. In addition, in the email I sent, I mentioned I was going to NRT for a week and the membership rep I contacted included an attachment with a list of restraurants, clubs, places to see and things to do in NRT... Nice touch since I'm not a member yet (or maybe that's the reason and from there the service would only go downhill ?).

Anyway, the email I received contained more information about NRT than Amex Centurion provided me with (but then again is that surprising ?)

I might be tempted to take out a membership...