I am good friends with who may be the biggest Ball Python breeder in Central Indiana. He uses aspen...but he also uses this substrate. And I used to use Aspen. However, and you should know this, Indiana winters are very very dry. Having gas heat, further drys out your air.
-SpiderBP
Haha...I didn't finish what I was trying to say here....the Reptibark holds humidity far better than Aspen. That is why I am using it right now because it's so dry in my house.