This is a rather old post and the resurrecting posts aren't really adding in anything new. Any distro that is built from another distro is broadly compatible - Ubuntu will accept Debian .deb files and OEL/RHEL/CentOS/SL will all accept .rpm files from a single source - unless otherwise specified by either the file maker or the distro maker.

Closed this off because I can't see a point where this won't go "no it isn't", " yes it is", "nu-uh", "uh-uh no takebacks".