Though much lesser-known than Mt. Pulag, the more difficult Mt. Ugo trek should count itself as one of the great world-class treks of the Philippines.
Last January, I was finally able to do the two-day traverse of Mt. Ugo with Trail Adventours, which had been long recommended to me as a trek of outstanding beauty. I had actually won not one, but two free day hikes from Trail Ad during the Muni Meetup: Travel & Truth, and decided to combine them into a weekend.
The actual distance of the trek is around 30km over two days (12km on day 1, 18 km on day 2), but the actual distance we ended up covering was over 40km.