Their videos are quite bad. Look at superstarteacher.com.sg.

Their teachers speak rather bad English., I am not sure you want your kids to learn anything from them. The CEO Kiang Heng Ti is also the science teacher (save money?). He speaks very bad English and struggles to pronounce even simple words.

He claims to have experience etc but I do not see him listing his specific experience and degrees.

Also office is in an industrial factory (save money again?) despite claiming to be in business for more than 10 years.

Go intern at somewhere more reputable where the teachers can at least pronounce basic words after supposed years of experience.