Not including tests it usually takes about 5 minutes. Including integration-tests it's more like 10-15 minutes. That's from a blank slate CENTOS vm.
What are the benefits you find from running integration tests?
Well they're part of our dev process (TDD) but in this context they're just useful to make sure all the dependencies have loaded, all the right ports are open, all the daemons are running, and everything is functioning as expected. Kind of a double-check after the build scripts run just to make sure nothing failed silently or got corrupted.