I have no experience with them, but I have not heard that. They are a species I'm interested in, so I've done some research on them. They are pretty similar in care requirements to a CDT from what I read and heard. They ARE more prone to pyramiding than some species.
Acclimating wild caught Chacos can be very difficult if you start with un-healthy animals to begin with......However, LTC or CBB Chacos are no different than any other Tortoise.........