Plenty of people here use it without issue. I use a mixture of substrates that includes Eco Earth in several of my cages. Until just recently I used Eco Earth alone in my gtp cage and hoggy tank where she burrows all through it without issue.
As for the anal passages it sounds as if your vet was referring to an impaction which can happen with many substrates if to much is eaten.
And as for clogging the nostrils I had a big problem with that using some cypress mulch from Lowes. It was given to me but as she rooted around it clogged her nostrils so I threw it out. Using Forest Floor I never had the issue add its much cleaner, uniform, and less dusty.
Being these post were from 2011 I think that is plenty of time to consider it a good test. Now we just need Tree to ring in.