We had a bachelor party of 9 and book 6 rooms at Makati Diamond Residences.
The staff was friendly and accommodating to all of our needs (early check in, late check out, assisting with logistics, etc).
Our party used the amenities (gym, lap pool, sauna, steam room, etc) every day and found that they are in good condition.
The location is amazing as it's directly across from the Greenbelt malls so food & shopping was very close.
If there was any critique, it's that laundry service was really expensive and some of the rooms can use a light update (chip wood, tiles, etc).
Overall, I strongly recommend Makati Diamond to travelers that want to stay in the Makati area.