So, now that we have two supported build systems in TFS, a question that often arises is, "Which one should be used?" Lots of people who have been using TFS for years have put a lot of investment into the build workflows, infrastructure, and customizations, so it doesn't make sense that they switch all their workloads to the new system. I would advise using the new build system going forward as it promises to provide more flexibility, as you will see in this chapter.