Personally I do think paper towel is a good substrate. The only thing that I dont like about it is; when that when it gets well the water spreads through the rest of the paper towel and after the paper towel dries again its turns all "weird".....lol. This means the every time I spray my leo or he tips over his water I have to put in new paper towel. That is the only reason I wanted to get my leo on a new substrate. I think I leave him on the paper towel.
Cypress mulcch was one of the main substrates I had in mind for the snake, but I also think that beta chip is cool aswell as the carefresh.