Mine is horse hide, and although I don't have a cow hide holster to compare it to, (supertuck or otherwise), I'm very happy with the horse hide. I've had no irritation where it hits my skin, and I wore it the past 2 days at work, for over 8 hours, part of which is outside, and it's hot here in Florida. As far are which is better or which breaks in easier, I have no idea. But I can say that the horse hide is very smooth, and that I would recommend a Crossbreed holster in an instant with no reservations.
So far the only thing I've found uncomfortable about carrying, isn't that bad and has nothing to do with the holster. It's the fact of how tight I have to keep my belt to keep the gun from sagging. This could be because the XD with 11 rounds of .45 is heavy, and could also be because the belt I have is kind of cheap and old, so I will definitely be investing in some better belts in the near future. Other than that, no problems so far.
"Breathe when you can, shoot when you should."
"Qui desiderat pacem, bellum praeparat; nemo provocare ne offendere audet quem intelliget superiorem esse pugnaturem"