Having worked with both systems, Debian CI does not focus on system integration. Fedora CI and Debian CI are more similar than different, but Fedora also has an OpenQA instance for doing the system integration testing as openSUSE does. openSUSE's main weakness is that they don't do deeper inspections of RPM artifacts, the dependency graph, etc. They don't feel they need it because OBS auto-rebuilds everything on every submission anyway. The Fedora CI tooling absolutely does this since auto-rebuilds on build aren't a thing there, and it's done on PRs as well as update submissions.