What I like about Conga Composer is that it's much easier than Salesforce's native templating. It's simple to add merge fields, write queries to pull data and access up to four levels of related objects. This makes it very comfortable to get all the needed data into templates.
We can use Word templates with Word boxes and customize everything. Its conditions are very easy to write and hide content based on requirements. When used with DocuSign, Conga Composer can calculate currency fields that DocuSign can't.
We can default to PDF and hide content to reduce errors. We can generate invoices by clicking a button and hiding tables, which we can't do in DocuSign. We can download and attach documents to notes and attachments or any field we require.
The solution with Salesforce allows us to generate templates with a single click after some configuration steps.