Let me tell you that it hasn't been very fun converting my workflows over. You have to look at tickets a lot differently as the tickets are no longer static but are workflows. For example, if you had a workflow using Helpdesk 6.5 that created a ticket and then went to an approver to approve, it would be be different in Service Desk. When you create a an incident in Service Desk it goes through the Incident Management workflow so if you were to create a ticket, you would essentially have two workflows running in parallel (Incident Management and yours) which may not be what you want to do.
What I've done is kept my workflows separate from the Service Desk one but integrated it into the same Process Manager so that they look like incidents but they're really not. That way my workflows run alongside the Service Desk and you just have to modify some of the reports to look for these workflows.