Just my experience and opinion here...but I would not use it for a couple of reasons.
1. We used it for our very first snake and it loved to burrow in it. We thought this was great for it must have made the snake feel like it would if it was in the wild. One of the problems was the Eco Earth when dry is quite dusty and fine, it would get in the nostrils of the snake, this problem also occurred if we kept it moist, but then it seemed to pack the nostrils till they were plugged. Over time the snake started to sneeze quite a bit.
2. When the snake releases it's excrement it has urates, stool and a liquid substance(sorry do not know the technical name), all of which contain bacteria and microbes. In the Aspen it all soaks up in the shavings directly around the actual excrement making it almost completely removable. In the Eco Earth the liquid portion soaks into the minute fibrous particles and does not always from a nice neat clump to remove, esp. if the Eco Earth is moist at all. Thus bacteria, microbes and parasites have a better chance to be spread in the Eco Earth.
3. When both moist and dry Eco Earth is very easily tracked into the snakes water bowl. This can then be drank and potentially cause impaction, not as much of a concern with bigger snakes but it is more of a concern with the smaller younger hatchlings and juveniles. Aspen is seldom tracked into the water dish and is shredded or shaved large enough that it generally can't be drank.
4. Add behavior 1.(burrowing and inadvertently inhaling the Eco Earth) to issue 2. (higher chances of bacteria, microbe and parasite growth in the substrate) and you have a higher chance for a respiratory infection which happened with our first snake, whom we no longer have.
After the incident with the first snake, we immediately changed to Aspen. I find it is much easier to spot clean, the viv/tank/tub stays cleaner, don't have to change the water daily due to substrate in it, all of our snakes love to burrow in it, it is far cheaper and it is recommended by the reptile vet.
I am not saying that others have not managed with it, this is just my experience and opinion. Some thoughts to consider.