Haven't got around to making a decision yet but then again, I'm not going to start pairings until maybe March so eh, not at the forefront of my mind. I currently keep all my snakes on aspen since I've had problems with snakes spreading feces all over their tubs, and incidentally themselves as well, in the past so I don't find it to be very sanitary personally... abscesses on hemipenes are a big deal though.
So, still don't really know which way I'll be going but I'm digging Ladybugzcrunch's carpet substrate so maybe that will be the one.