I've stayed at several PDX airport hotels, including the Hampton Inn and Aloft. The Residence Inn is by far the nicest and best value.
One key is the dedicated shuttle: the Sheraton, Hampton, and Aloft have a shared shuttle that can easily turn what should be a 5 minute ride down Airport Way into a 20-minute excursion with several stops. Basically a city bus. The Residence Inn shuttle by comparison feels like a private taxi.
Was impressed that they took a shuttle reservation (the other hotels just say "come down when you're ready and we'll call the shuttle, you may have to wait 15m and if there are too many people you may have to catch the next bus so leave plenty of time"). When the time came, they called up to the room ahead to let us know they were ready to go. The shuttle driver was super-efficient and friendly.
The other PDX airport hotels seem a bit tired and worn out, but the Residence Inn was very clean, bright, modern, and fresh. We stayed in a studio suite that was surprisingly spacious. Kitchen and fridge were great, kitchen was well stocked with utensils and supplies. They slipped the bill under the door, which was great to speed up early a.m. departure.
Really couldn't be more convenient to MAX. A little airport noise, but not bad at all. Noise from HVAC was very reasonable unlike Aloft.
Overall the cleanliness, shuttle efficiency, room size, and in-room kitchen are well-worth the slight premium over the Sheraton, Hampton, or Aloft options.