I am currently investigating migration from TFS to VSTS. The one issue I can't seem to find an answer for is whether there would be a way for us to build our installshield projects in VSTS. Any help will be much appreciated.
InstallShield requires a private build server. You can't use the hosted build servers because InstallShield isn't installed. It can't be XCOPY pulled in, requires admin to be installed and has a license.key DRM scheme tied to the MAC address.
WiX works better on the hosted servers but still isn't perfect because you have to disable MSI validation. Validation requires admin rights or it fails.
Other then this limitation, I've migrated many TFS environments to VSTS and it'll work just fine with InstallShield.