We've currently offline/FTP based solution through which our vendor provide product information which to be displayed on our website. However we would like to provide webservices API through which they can provide thier product information to us. Could you please suggest on basis of your experiance what would be better choice?

1. SOAP based Web service

2. REST based Web service

and what should be data exchange format SML, JSON , etc (Note currently it happes through files upload using FTP)