RPM is part of Linux standard base, congrats on not following the standardization documentation.
There is only one gnome 2 fork, Mate. Cinnamon is gnome 3 fork, while Consort is a gnome 3 fallback fork. Mate will most likely be abandoned once wayland begin to replace X, for not enough developer to update the whole repository, cinnamon, lose relevance has customization feature get integrated in gnome 3 (not that it at a good customization state, but getting better at least). Consort still have to see if will worth it, but it does have better reason to exist, which is keeping the fallback mode, which is better if done correctly, has it permit gnome 3 compatibility while keeping gnome 2 paradigm.
More the kind of person that can go for a simple windows manager (for a minimal interface) or kde (but for lack of time combined with OCD reason I never got time to fully dive into it, if actually fit), but don't care really, so mostly stick with what already there, has my workflow mostly involve the CLI, a web browser and lot of VM.