I was introduced to them a couple of years ago - love them!! Do they have Rumbi's in California? They have really good sweet potato fries. Arctic Circle had them for a while, not sure if they still do.
my school has a place that serves them in the food court. i tried them and they werent anything that great to me. i like sweet potatoes in their traditional forms, but these were just...meh. maybe i need to try them somewhere else