SharePoint Designer is free and does have its place for workflow, but there are some inherent limits with the product, such as:

-Workflow design history: No version control in different versions of a deployed workflow. Only the latest version on the server.
-Deployment: The workflow has to re build the entire workflow, from a dev, test, live environment. This is roles, actions
-Can only work with information in a site, not across a site collection. The following cannot be done:
-Archiving items to the archive site collection (Another site collection)
-Grabbing information on another site or farm
-Creation functionality. Can’t create a list\ library\team site. This is a design action, not content creation.
-The flow is sequential, therefore you can’t go back a step in the process.
-No automatic escalation process if there’s no response.
-No back up approvers
-No Parent / Child processing, share of information between processes. A workflow can’t kick off another process.

It's still a great product, however, and this post is more of an FYI.

For further information on workflow with SharePoint Designer, this free webinar maybe useful. Link