In my opinion, the difference between 如来禅 and 祖师禅 is that 如来 is more suitable for ordinary disciplines while 祖师禅 is more for special students like 六祖 himself since it is created by him. So which method is better? It all depends on our aptitude, students who are in school A may only achieve 70% of their potential but when they switched to school B, they may develop 90%, and vice versa. Then you may say 如来禅 is more 正中 because it is taught by the Buddha himself. The truth is, the collection of sutra in our possession is only the tip of the iceberg, the Buddha is teaching many other forms of sutra in other realms. For example, it is mentioned in our sutra that the Buddha is teaching through emitting various forms of lights in the 光音天 instead of through words and sound in the human realm. Then we also know that 观世音菩萨 is teaching in a rather vulgar form of 青面獠牙 ghost in the ghost realm. We will find the ghost realm's dharma vulgar in a similar way people in 光音天 find the human dharma as vulgar. Different sentient beings have different types of neuron circuits and thus require different sets of key or dharma to unlock. For example, some students find it hard to understand calculus taught in math textbooks and this particular Australian RU-vid lady explains calculus through stories in order to facilitate the working or learning of certain sets of neuron circuits. 一切有为法如梦幻泡影， 如露亦如电应作如是观。This is a famous verse from the 金刚经 which 神秀 ,六祖 and many others practised. If I were to write a verse like 神秀 and 六祖 to describe the essence of 金刚经, I would say '我有一帘幽梦 不知与谁能共 多少秘密在其中 欲说无人能懂'。Sorry I must borrow this from others because I am not educated in Chinese and can't write beautiful and meaningful Chinese verses. For those who understand Buddhism will know that so much is contained in a single 念头 and I hope they can appreciate my borrowed verse 🙏
