Account to install Oracle with on Windows platform

Folks,
  I have always worked on Sun/HP platforms in the past. There it was
clear to install the Oracle kernel under an "Oracle" OS account, as
opposed to root.

  However, now I have to install it on a Windows 2003 64-bit platform.
Do most DBAs installing on MSWin install as the "administrator"
account, or also create an "oracle" account and make it a member of
the admin group?
What are the pros/cons of it on MSWin?

11g/ASM/RAC in case it matters.

thanks.