A lot has been said regarding taxis in Manila. Many will refuse to use their meters if they recognize you as a tourist. Even if you are local they may refuse as well. My experience during my recent visit was this. I met with some friends who came to my hotel by train and we were leaving for dinner. My Filipino friends knew I was not accustomed to riding a bus or train so we flagged down a taxi. My friends told them in Tagalog where we wished to go and the driver quoted a price that seem very high for the distance so we refused. That happened 2 more times before we were able to get a taxi who would use the meter. Another time I was in Ortigas and it was early morning and there were many taxis everywhere. I wanted to go to Makati and none would use the meter, their excuse is because it is late. I just accepted the fare from after negotiating it down by 150 pesos, he wanted 500. So its easy to say just wait for a metered taxi but you might wait a long time.
The official airport express taxis are well run and they will use their meters but you cannot flag them down in the street. The one I use when I arrived was very nice. After I got to my hotel safely and direct, he gave me his number and explained that he can pick me up if I call his number but he cannot be flagged down. I used him several times knowing I would have to pre-arrange the times and also knowing that he may not be available at a specific time which is fine if you can do that. He would always use his meter. I used him for pick up and drop off at the Mall of Asia, restaurants, etc. The times when my schedule was unpredictable, I had to use a flagged down taxi. On my last day in Manila, I had a 7pm flight. I called him at 12:30pm to see if he could take me to the airport but before that if he could give me a tour of Manila that I didn't see. We agreed that he would pick me up at 2pm after I had lunch and checked out. We drove around for 3 hours before dropping me off at the airport. He showed me different sights, stopped at different places where he took my picture and explained things that I never would have seen otherwise. When we got to the airport the meter said 780, I gave him 1000 and thanked him. He invited me to his home the next time I come to Manila. I kept his number and actually referred him to a colleague that visited Manila 3 weeks later. When my friend returned, he couldn't stop talking about Resty, the taxi driver. I have his number for future reference and referrals.