My main feeling is to agree with member emsr2d2, as in my heart I like to think one is not better than another.
Only, we are talking about business here aren't we? If your training to enter a corporate environment I'm thinking your intentions are to achieve success. The accent in which a student learns to speak English should be in tune with the main & most prestigious, or upper class, accent of the environment or country they are going to have to communicate within.
-(I found this on our good friend wiki- The notion of a "standard" language in a speech community is related to the prestige of the languages spoken in the community. In general, "greater prestige tends to be attached to the notion of the standard, since it can function in higher domains, and has a written form.)
If the student is heading for the world stage firstly I believe having a grasp of several languages, not just their native tongue & english, is a must. Working in a global business environment the accent for english study should be as neutral as possible, RP or Received Pronunciation has always been a popular choice, especially among foreign correspondents & journalists, although it does appear to be diminishing slightly.
Thank you for taking the time to read this, everything I have expressed is only in my most humble opinion & I hope you find it helpful.
Cheers, Kay.