I found there are 3 major mobile internet operators in the Philippines, Smart, Globe, Dito. But wondering which one is better for internet surfing when stay in the Philippines ?

Both top 1 operator SMART and top 2 operator GLOBE are good in the urban area that you can enjoy surfing internet and watching online videos without problems. But for rural area, SMART telecom is better and wider coverage of the signal.

Look these prepaid internet promos from SMART Telecom and GLOBE Telecom could save you some money:

https://smart.com.ph/prepaid/promos

https://www.globe.com.ph/prepaid/promos.html