I stayed here for 5 nights in February of this year on points - by far the best W I have ever stayed at, and an overall phenomenal hotel. I was upgraded to a massive suite (SPG Plat) with stunning views of downtown TPE - plentiful bottled water and some pretty good chocolates awaited me in the room as well. Main (yes there are 1.5 baths) bathroom was stupendous, with a great shower, nice towels, and full-size (or near full-size) bottles of Bliss products. The soaking tub has a small television mounted over it and a nice corner/niche with floor-to-ceiling views of the skyline.
Service was impeccable, and the food downstairs was very good as well (though I would still recommend first-time visitors to eat outside of their hotel as much as possible). Haven't stayed at the other SPG Props in TPE, but I would gladly return to the W in a heartbeat. Coming back to American hotels is now like returning to United E- seating after sitting F in ANA...