Thanks so much for your comments.
I understand that TT will use PTH as the first language for teaching and everyday they will have NET to teach English for 1 hour.
This is the reason that makes me feel hesitated as I prefer them to use English as the 1st language and have regular PTH lesson everyday instead.
It seems that St Nicholas would have better training in English langauage. However, as I notice from SN's website, their students didn't get very good results in P1 application, esp for DSS and private schools.....Nothing is perfect I am afraid.