I just don't like sand in general. I mean, they don't live on it in the wild anyways, and it seems sort of unnatural when they try to run or walk across it. The repti-carpet or indoor outdoor carpetting of similar style seem to give more of the hardness of the ground where they are from, and they can't ingest it (as long as you cut off any loose threads). I used repti sand for a while (which is the non calcium carbonate sand), and it looked nice but didn't function well. Plus when I was cleaning it out, I found small bits of dried feces (which is not good considering my dragon had parasites at the time).
I think I'll stick with the repti carpet for now. i think I might get some bed-a-beast or similar substrate and make a nice little bed for him on the warm side though. Bed a beast is supposed to be completely digestable (even though my vet said he's even seen a couple impactions on that stuff). Basically, when I told my vet I had him on sand, he told me that he has done to many surgeries to remove sand from a dragon to ever tell me it was safe to use.
I might switch back to sand in a couple of years someday though, I just want the best for my reptile though. It makes me feel uneasy that even if he wasn't getting an impaction from it, if I had him on sand he would have at least tiny amounts of sand in him (they sure like to lick their surroundings).
later