I've stayed at both properties numerous times over the last year or so. I like both -- each has its minor differences but I've been quite happy with both. If you want a big corporate hotel, go for the GH. If you want something more intimate, the PH is best.
I'm Diam and have always been given the same room at each property: an extra large room that overlooks the Cathedral at the PH and a corner room at the GH. Happy with both.