Having said that, unfortunately there is not an answer that fits all. Just because an organization has chosen to implement a classic scenario, it is not to say that they could have not implemented extended classic. This decision is entirely based on the business processes being implemented, their current environment (eg. SAP or legacy?), and the critical assessment of user acceptance.
On all my projects, I usually utilize the business blueprint phase to help determine the implementation scenario, as it best allows us to capture the true requirements of the organization. In situations where a decision for classic or extended has already been made prior to blueprint, I utilize the blueprint phase to challenge and finalize the implementation scenario.
You might want to review the "SRM Functionality Matrix".
This was first published in April 2005