I used to use Eco Earth for about a year and quit. The advantage of humidity isn't worth the mess it made as well as if you let it dry out, it gets really dusty and yes it can mold even though people say it doesn't. I use aspen for both my snakes and can easily keep humidity of 50%+ by just covering the top of my bp tank and with my red tail boa, she is in a Pro-Line cage which just holds humidity without even trying. I personally would not use Eco Earth in a wood cage as you need to keep it moist 24/7 which could cause the wood floor problems.

As for substrate changes, regardless of what you choose, you will need to change it out every couple months. Any substrate is going to soak up the liquid part of pee/poop. Aspen is just much easier to clean out of cages than Eco Earth which like I said is a mess and gets EVERYWHERE. Plus spotting a poop on aspen is easier than trying to spot a brownish/black poop on brownish/black substrate.