ESL Starter are actually the recruiters for Teach and Learn, who run this internship program, so my review is of the program with Teach and Learn.
My main qualm with this internship program is that as an intern you are placed on a Chinese student visa. As the Go Overseas website states, "Foreign interns in China need to have a "special business F visa" that specifically prohibits compensation. Be wary of any provider promising paid internships in China." (https://www.gooverseas.com/internships-abroad/china).
With Teach and Learn, you will be placed on a student visa, not a business F visa. But, with the program, you will be working as a Teacher. During our induction week, we were told that we were not to tell anyone that we were teachers, and instead had to say we were students.
If you are caught in China on the wrong visa, you can be fined and may not be allowed to enter the country again for a certain period of time. If you are willing to risk this, it's up to you, but I do not feel that ESL starter was upfront with us about the fact that we would technically be working on the wrong visa, which is why I want to warn potential interns of the risks. In fact, some interns were "found out" by the police and had to leave the country and enter China again on the correct working visas.
The Mandarin lessons you are meant to receive every week will vary depending on the school or University you have been placed at. Some people only received a one hour "lesson" from one of the teachers at the school. Others were "taught" Mandarin by University students. They are not proper lessons and definitely did not teach us enough Mandarin to pass us off as the Mandarin students we were meant to be according to our visas.
Your experience on this program will vary depending on which school or University you are placed. Whilst I enjoyed the place I worked at and they provided decent accommodation, I was aware that I could be earning a lot more (and not living in fear of being caught teaching on a student visa!) if I had instead applied for a proper teaching job in China.
The good parts of this program are that it's only 4 months long, you teach a maximum of 15 hours a week, and you meet other interns during your stay in China. Also, a lot of interns were people who couldn't get a working visa in China - non-native English speakers and people without University degrees. So for them I guess this internship was good, as they couldn't have got a proper teaching position in China (a working visa requires you to have a degree and be a native speaker). But for others, I think you have to think about whether you are willing to enter China and live there on the wrong visa.