I ended up staying at the GH Taipei. It was solidly OK. Certainly not on par with the vast majority of properties discussed here - though noting the limited options in Taipei.
Next time I return to Taipei, I will likely try the W.
Overview: A quality (if aged) western business hotel in the heart of the CBD
Strengths: Service, breakfast restaurant, location
Weaknesses: Rooms are getting old
Full review
here.
Apparently the hotel's location was a Japanese military location many years ago. Rumors swirl about what happened - but indeed some suggest the hotel is
haunted. I did not see any ghosts or other paranormal activities.