I was wondering if anybody here has implemented Address Verifications and can make a recommendation ?

I have done some research and have found out our possible options are;

- Purchase Online Database Service and pay per use (for all customers who signup).

- Buy the Data (on regular basis because of frequent updates) and install it on our own Server.
Customer station will call our Server online. No Pay Per Use fees. But instead need to pay for the Data and Server Maintenance.

- Customer buys the CD for each station (on regular basis), installs it, and then our App does a "LOCAL" call via DDE / DLLs.
(nothing online - No Pay Per Use fees, no costs on our part - customer buys updates directly from the Data Vendor).

Would appreciate any inputs.

Thanks.