We currently use separate Search Types for Customers and Vendors. What are the ramifications of all

I realize that there is no issue with establishing both the "payables" and "receivables" flag and generating payments and invoices.  But, what are the less obvious issues you run into with end users (confusion about finding the correct customer/supplier number, running Aging reports, etc?), and what do you recommend as the Search Type associated with the Address Book record?

Thanks!