What's the best Scan Software for document archival

Anon,

Can you clarify a bit? You seem to be asking about an integrated dms....
-There is the scan software itself; even the most basic will drop the docs into a queue for filing.
-There is OCR, which will help grab information from the scans and autofill forms for the metadata tags that you seem to want.
-There is the DMS, where all of this will get archived and accessed.
-There is the ERP system, maybe tied to your accounting system or CRM like salesforce, where the active customer/vendor/employee data will reside, with these documents as reference material.

It sounds like you need to start from the top; what system are you using to track the customer orders? That would drive your choices. QB, Salesforce, Xero all have add-ins (and some core features) that allow this. For example, in the simplest instance you scan a doc; it hits your "to file" folder; in Xero you go to the PO and click the upload button. The doc is now accessible through the PO. However Xero has virtually no DMS/CMS capabilities, so you can't search for "PO's from Joe's Garage" on a document level. Xero would allow what you ask, but less automated than a more expensive (to license and implement) solution. There are also lots of point solutions that may be appropriate for your needs. For example, if you are on SF, maybe use Captricity to capture the data so PO entry and metadata tagging are one step, reducing work and errors. Of course Captiricty works with other vendors as well (as a CSV import); the question is, what is the process?

So; start at the top.