Khun But has a very good selection to choose from. Better than majority of the fancy shops I've been to in all Thailand.The little cart is just to get road side attention. He invites you to the patio where he has the real stuff. I've tried 5 different strains and the product is so fresh, beautiful to look at, and smokes smooth. He doesn't charge a ridiculous amount of money either. Fair and honest prices and he's more than happy to work with you depending on what you want to purchase.
As I understand it they are a tight group of growers who get their advice from an elderly man who is a master grower from the island. I had the privilege of talking with him while he was on the farm via face time. Nice group of guys.