We stayed here for about 6-7 hours after a midnight flight arrival and before an early morning flight the next day. It has a free shuttle, and you can call the hotel for the shuttle after your bags arrive. The hotel is conveniently located basically on the airport grounds (you can see a runway from the hallway). The shuttle driver and check-in staff member were both pleasant and professional.
The room was clean and nicely furnished with typical Hampton Inn furniture. The bed was plenty comfy. There is a breakfast set-up in the lobby but we didn't eat there. The shuttle in the a.m. got us to our departure door at PDX quickly.
Here's some tips for those of you arriving on a long, late flight like we did but have no car to go and drive to find something to eat after midnight. I actually called the hotel staff several days ahead of our arrival in an attempt to figure this out. There is no restaurant at the hotel, but there is a very small "store" off the lobby where you can buy frozen stuff like Hot Pockets, I was told (I saw the "store" but didn't check it out). I was also told by a staff member that the same hotel shuttle stops at another hotel on the airport grounds that is next door to a 24 hour IHOP and although the driver cannot take you to the restaurant directly they can drop you off and pick you up at the hotel next door. We did not try this, but fyi. I was also told by the hotel that a local Dominoe's will deliver to the hotel 24 hours/day, but I went online to check this out and it isn't true - for the night we would arrive they stopped at midnight. So, what to do?
Figuring that PDX gets lots of late night arrivals from the East Coast, I looked up their guest services number and called them. A very nice woman gave me the best solution to landing all tired and hungry ... There is a 24 hour "Oregon Market" in the terminal where you can pick up "grab and go" sandwiches before you go down to baggage claim. So you can buy a little late night dinner and take it with you to the Hampton Inn. Of course, once we landed we weren't hungry so we didn't pick anything up at the Oregon Market.
I kind of wish the staff person I called at the Hampton Inn was a bit better informed about late night food options, so I'm passing this info along to you in the hopes that my "research" will be helpful to someone!!