I never know Philippine has this kind of place. Last time I visit Philippine I can't eat their rice. No offend here Philippine friend, but rice in Manila test bad. A lot of Slum too. Last time my employer wanted me to stay at Philippine for a year with good incentive, I had to quit the job because I have family and I really don't know how to raise my kids there to be a Thai speaker, also security problems.
When Dan Brown's novel mentions Manila as "the gates of hell," he was right there; everything here is in bad condition and with a new political circus brewing up here, things are going to take a nose dive. Security issue here in Manila is a joke as some cops here are corrupt. As for the slums, I would advise to stay away from them; if you are a well-dressed Filipino passing through there, the chances of being robbed or swindled are high and if you are a foreigner, the chances are higher.
I can't blame you if you quit the job considering that Manila is getting worse, in fact, the NAIA airport should give hints and signs as to what most of Manila looks like. As for cities south of Manila such Cebu, it looks cleaner as it hasn't been touched with the reckless urbanization and political mismanagement Manila has experienced.
Also, I am not much offended since much is true though I am not sure about the reactions of other Filipinos here...
Some cultural aspects that I like about Cebu City....
Cebu City is the oldest city in the Philippines, actually. It has an abundance of Chinese, Japanese, and other western foreign investments / presence.
Taoist Temple in Cebu City. There is a large Chinese-Filipino presence in Cebu
Chinese-Filipino in Cebu's Taoist Temple
Cebu was considered to be the original capital of the Philippines as this was the place that Spain first had landed and made converts but they choose Manila as it was "strategic location" due to its bay.
You're also right about the foreigners saying "Philippines is bad place" as most of them are going here in Manila. To be honest, one of the consequences of reckless urbanization of Manila is that it is getting too crowded and not only that, the concept of Metro Manila itself - it was created as the national capital region of the country that is divided into cities, each having its own local government but no "central government" to oversee the development of the city.
In simple terms, if you are an urban planner, Metro Manila would be your worst nightmare.
As for Vietnam-Philippine comparison, due to current political instability (which never ends) here in the Philippines and the looming power crisis here which will happen around 2015, it is likely that Vietnam will surpass us in economic standings here in ASEAN. I am not sure how but since our politicians like to shoot ourselves on the feet, nothing will change here.