I've been invited to stay a few nights in Manila with local friends. Are there any area's in Manila that would be classed as unsuitable or just dangerous for westerners to be visiting?
I then head to Butuan , which according to the UK government IS dangerous.....

Stay away from Tondo and the port area at night - your local friends will keep you safe.I have 25 years of living,working and vacationing in Manila and many other places in the Philippines and never had a minutes concern - Filipinos will tell you how dangerous other places are but always say their own area is safe
My wife and I own a house in the suburbs and we keep a car there for holidays - we drive in Manila and long distances to the provinces without being concerned for our safety. The only places in the Philippines that would cause me concern are the Muslim areas of Mindanao - Zamboanga for example and some of the southern islands like Basilan or Jolo - you would need to be an absolute idiot to go there.
Manila can be a lot of fun if you have someone that knows the place - it has some of the worst traffic you will ever encounter.remember there are 16 million people there with an infrastructure that really cannot cope. The San Miguel beer and 15 year old Tanduay rum are excellent and cheap, also try the local palm spirit called Lambanog but take it easy as the stuff is rocket fuel!
If you want to stay married take your wife with you as the Filipina are something special - I married one.

I'm still single, have stayed in Valenzuela City and been invited to Pasig city this time.
Valenzuela seemed fine and my friends were with me all the time even though I seemed to get quite a bit of attention.