I've been following this thread with interest for a while, and not sure what to answer, as my favorite RC depends on the day it is!
But right now my favorites are:
4-AcO-DMT - peaceful and deeeeeep. Incredible substance, very spiritual and perfect for meditation. The duration is not too long. Never had a bad experience with that
5-MeO-DIPT - Foxy. For working with the Muladhara and the Kundalini, Foxy is hard to beat. Very physical but can be overwhelming (generally in good way)
MXE - Did not use it extensively. I stay off low (10-20 mg) dosages, but I can hole with 35-40 mg (I have no tolerance and I like it that way!) the M-Hole is so unbelievably deep that puts everything else in shame. Not emotional at all and does not have the healing potential of Ayahuasca or even 4-AcO-DMT, but it shatters my mind into Neverland in ways I could not even find possible before. I also believe that using it once every two months helps keeping the experience fresh, and keeps the tolerance low.