Excellent course, if you're ready for it.
I spent three weeks there, concentrating on improving pronunciation. Excellent course, which I have no hesitation in recommending and would love to go back. So why 4 stars not 5? Because it won't suit some people. Practically no-one speaks English in Chengde, so you need to have reached a suitable level of confidence (if not language proficiency). That said, everyone is really friendly and patient- not like some of the larger cities in China and the rest of the world. Homestay is worth it. Of course, its a bit difficult staying with another family for several weeks- even without the cultural differences. But its a great way to meet locals and understand culture, as well as language. The teachers will respond flexibly and patiently to your needs- but you have to know what you want and state it clearly. Overall, if you have a certain level of proficiency and confidence then I recommend this wholeheartedly. But it isn't the place to start.