I'm heading out to the P.I. for my fourth holiday trip this April.
Not once have I felt the slightest threatened or worried.
Last trip I went to Mindanao (Cagayan De Oro and Davao), were according to some it's very dangerous. I didn't personally see anything particular to support this belief.
As you are not going anywhere near the debated "unsafe" island of Mindanao you should be perfectly safe.
The only place I tend to be a bit extra careful in is Manila. It's a big city and probably not the best place in the world to, for example, end up alone, drunk and in some kind of red light district...avoid that and you should be fine.
I also second what everyone else already has said, don't flash cash, don't be rude etc. etc. (Advice true for about 95% of the world).
I'm sure you'll have a great trip.