I have spent multiple years in both those cities, and I would say SGN is much easier as a tourist destination. MNL can be great, but it's harder to have it be that way IMO. You kind of need a friend or local there. SGN is set up for tourists more, and has more popular food options.

So I'd also vote for SGN.
But if you really want to try the Philippines, I'd go to CEB as suggested above. It's easier and has some of the monuments from the old colonial days, and has plenty of food options. Beaches and the nightlife type beaches are within easy distance also if you want to get out of the city for a day or two, such as to Panglao/Bohol, Dumaguete or Siquijor. Still if you do go to MNL, it does have shopping and some culture/museums/history. Stay in Makati or the Mall of Asia area, use Grab not taxis, and do some research on the city before you go.