Ranked in these QuestionsQuestion Ranking
Pro Follows the UNIX philosophy
It only does one thing and that well.
Pro Part of LSB
It is part of the Linux standard base.
Pro Very easy to create packages
It is very easy to create packages for it, you just need a small spec file.
Pro Standard archives
RPM packages are simple cpio archives that have additional compression support.
Pro Easy to create packages on non-rpm based distros
This makes maintenance and support easy.
Pro Much more advanced than apt
Con Many forks
Currently there exist rpmv4, rpmv5 and distribution specific forks like Mandrake's urpm.
Con No interaction
RPM does not support user interaction upon install.
Con Plenty of different frontends
Almost any rpm distro has its own frontend for rpm there is zypper, yum, apt-rpm, dnf, poldek and many more.