I tried this Subtle Art Soap Co. Tea Tree and Charcoal that I got with the gift card @Garry357 gave me. While I liked the performance of this base in another flavor, the charcoal and tea tree oil in this one seem to ruin the performance of the soap. It looks kinda cool in the tub because of the charcoal, but it doesn't lather as well, and the real problem is there is some astringency that makes it so it isn't slick and doesn't provide good lubrication. I started the shave with a straight razor, but it was not sliding, so I switched to a safety razor, but that dragged and nicked as well.
This soap was on clearance, and I can see why. It is like a failed experimental pseudo medicine wrapped up in a shaving soap that doesn't work properly. I would suggest you use tea tree oil only in soaps that do not need to provide lubrication. It would work a lot better to have the added ingredients in a facial soap or pre soap (I wouldn't buy either anyway.) and then just to shave with something else.