I use paper in Steve's enclosure. Sometimes newspaper, generally those giant brown paper bags that you put leaf litter in. Can't spot clean as easily and you have to be more vigilant about things, but it's easier to deep clean and Steve doesn't manage to get some substrate in his mouth.
I believe we were using aspen up until Steve managed to get a few chips in his mouth while wrestling his dinner. He came out unharmed, but it certainly freaked the poor guy out. I don't know if it's a problem for other snakes or if mine is just klutzy, but for me it's much easier.