Tallow or Vegan?

I prefer tallow, generally. But there are some very good vegan soaps as well (Saponificio Varesino is probably the best example). As long as it performs, I'm down. It's usually the other ingredients that make a bigger difference; lanolin, shea butter, kokum butter, avocado oil, tussah silk, etc.

I agree! But you will almost never see lanolin in a non tallow soap (only exceptions are sone razorock soaps). The combination of lanolin + butters is a match made in heaven in terms of slickness, protection and post shave.

Route 66 is a veggie soap that has lanolin. I've never tried it but I do have RazoRock The Dead Sea that is also non-tallow but with lanolin and that is a great soap.

There are some great non-tallow soaps: Nuàvia, Saponificio Varesino, Martin de Candre, Jabonman Eufros Meißner Tremonia, are at the top of my list.

I find that when I shave with a Feather Artist Club Single Edge, in a larger SE razor such as a King Cobra, Asylum, Mongoose, etc., I much prefer the performance of the tallow soaps and how they interact with the blade: At the top of my list are: Barrister and Mann glissant, Cold River Soap Works Select, Jabonman Eufros tallow, Mystic Water.

I can get a very good shave with any soap and a DE, but when using a SE, I find the shave better with a tallow-based soap.

Both I guess. My two favorite soaps are Saponificio Varesino and Mikes, but I give the edge to Mikes. Just by a hair though.

I find that for some reason I enjoy my tallow just a bit more than the vegan. My absolute favorite soaps: Barrister & Mann, Tabac, MWF, Reef Point, just seem to perform slightly better than my vegans. Just seems like they come out creamier and more protective. Could just be me.

I'll go with the consensus, both as long as they're good (duh).  I also concur with bufflehead that its more challenging and costly to produce an excellent vegan soap.  I have some excellent B&M vegan soaps but Will no longer makes any vegans and I believe the reason is the cost not the challenge.