To each his own as they say! I have seen quite a few cases of chameleons on here injesting substrate. I remember a Jackson's chameleon with a piece of mulch sticking out of his vent. I am keeping my cage floors bare!
Haha.. all my current and past cages have the bottom bare as a newborns!! However after talking to a few people on here I have a two cage setup almost finished that will have planted tubs in the bottom loaded with springs and pods.. I am actually very excited to give it a try however I made it where the bottom Will be easily interchangeable if I don't like the outcome..
However I have to agree with djturna here also.. the exoterra is probably a little on the small side for an adult panther cage and a little lacking on airflow.. I know they work great for smaller high humidity species.. but to each they're own.. we all find ways to make our setups work