The key to choosing a civil service examination and training institution is to improve the landing rate. There are three main factors that affect the landing rate:
1) The teacher taught well. So it depends on the teacher's background, qualifications and experience.
2) Students themselves. Different students have different acceptance ability;
3) Students learn well. From the choice of training institutions, the key lies in the service system. A high-quality service system can make students change from passive acceptance to active and loving learning.
So back to the topic: well, keys don't help you much. That's what others say: what suits you is the best. For reference only.