My wife and I have run across veterinarians who were not fond of the wild cross breed cats (bengals, savannahs). This included the vet office she worked at part time during her short retirement ( she consults now full time!). But each time a veterinarian took the patience to examine any of the three savannahs in this house, each and every one of them altered their opinion. The off ice she worked at, is our current vet, and they are always excited when these SVs come in. They whole office wants to visit as our cats are well behaved and they don't get to see many of these spotted kitties.
Others have pointed out problem cats come in all sizes shapes and breeds. I really think some people think "active" cats equates to "problem" cats. Not so.
As you read these forum threads, bear in mind, should a person have a challenge with a cat, this is where they would come and ask for advice and knowledge from the servants and breeders. So I can assure you, the rate of challenges appears far, far higher than the true rate for this reason. The overwhelming majority of servants never have found this forum. The members of this online community represent a very small percentage of savannah households. That said, there is an amazing amount of experience and knowledge to tap with our active members.
My cats all came from a breeder who welcomed us to visit the cattery, before the purchase. And I was fortunate to live near enough to pick them up in person.