THB I think I prefer rue as a regular teacher. I dont find it any less pleasant than caapi personally..I dont find the differences as drastic as others make them out to be. Rue is somewhat different..and it is beneficial to look beyond it as a simple ayahuasca analogue in my opinion and instead see a plant with a long history of human use with a complex mythology surrounding it as rich and elaborate as that of ayahuasca itself.
However, I have had Banisteriopsis Caapi that felt like it differed more from other caapi I have drunk than rue does..and I have had Banisteriopsis Caapi that was 3-4x the potency of other Banisteriopsis Caapi I have drunk..
This whole red, yellow, white, black vine thing(in the context of Banisteriopsis Caapi) I dont even want to address..becasue it means nothing when removed from the local amazonian folk context(s). There is no context for any of this by the time it comes from the jungle, to a vendor(and who knows how many) and then to you. Red vine to one currandero might mean Banisteriopsis Muricata, while some other vendor might have "red vine" that is Banisteriopsis Caapi..and white vine might mean one thing to one tribe or currandero and something else for another one. Botanically speaking, there is no difference..we have no relevant standard to compare here so it's a tiresome problem to attempt to deconstruct.
The only difference that is verifiable for us is between Tunkanaca and Caupuri ayahuasca, which are both still Banisteriopsis Caapi species and not even recognized as true botanical varieties, despite the obvious morphological differences. What differences might exist subjectivly for drinkers I cannot say.
I like to designate Banisteriopsis Muricata as red vine..and it makes a deep red brew. The effect of Muricata is extremely similar to that of Banisteriopsis Caapi. Other vines such as Alicia Anisopetala(called black ayahuasca by some) differ much more from caapi and rue both and dont even contain any known beta carbolines..to make this even more confusing, some vendors have sold alicia vine as "black caapi", essentially marketing it as if it is a strain of Banisteriopsis Caapi, which it definatly is not.
To make things even more confusing, we often talk about all these different strains of Caapi and the differences in effects, and then simply address Peganum Harmala as a single qualatative experience. Peganuma Harmala itself expresses a variety of alkaloid profiles based possibly on strain, time of harvest etc..and this is a phenomenon as far as I can tell that is largely unexplored. I do know of at least one person who works with both commercially available rue and rue he harvests himself in a region of turkey, and claims there is a very noticable difference in the quality of experience between the two strains.
So you see, I cannot even attempt to adequatly answer your question. All I ca do is address the inherant problems surrounding the answers that seem to be in circulation.
Long live the unwoke.