I was reading this thread before returning back to Portland and Oregon after a 2 year hiatus, and this time I stayed at the Hilton Portland and DT Portland.
The Hilton Portland was good as others have said, comfortable and quiet, and the room looking like it has been refurbished recently, along with the biggest TV I have seen in a non suite room, 65 inches! Breakfast credit was $15 as a Diamond, either the buffet or off the menu, which I picked something off and I thought it was pretty good.
The DoubleTree was alright, old room, but it was very large, as they gave me a 2 bed queen room. Breakfast for Diamond/Gold guests was a Continental buffet breakfast, with a $3 surcharge to have the full Buffet with the hot items. I thought the regular options were intentionally limited to push people to have the full buffet, but I didn't think they looked very appealing. I didn't use the 'free' Lloyds Centre parking as mentioned earlier as I didn't want to drag 2 cases through the shopping center and car park the next morning, but did get a park space right next to the hotel entrance, as I was leaving before 10am, and only needed to pay $2 to cover the parking until I left - better than the $27 self parking charge, which they tried to stick on my bill....