Being able to ship something is definitely important as there are a lot of junior (and even more experienced devs) that just can't seem to finish a project.

Also, stick around for a while after it's been shipped or deployed and see what kind of difficulties the ops guys have with it if it's a SaaS product or the customer support team has if it's a locally-installed product. There is a huge difference between shipping a working product that is simple to operate and support vs. one that requires constant care from an expensive ops or support team.