Be warned...this is not a normal hotel! It's a statement of 25-30 something hipness and although I had a fine stay at the Ace Hotel, if you expect a standard hotel experience, you'll be extremely disappointed.
The rooms are designed to be downward-chic styled to appeal to the young crowd. My room had a spartan bed in the center of the room surrounded by a sink and the shower. The toilet was near the entrance. The walls were painted gray with a poetic saying painted in black script across the wall above a long spartan board serving as a table. I didn't mind it at all but was desperate for a small fridge and coffee machine. Too pedestrian and uncool, I guess.
The old building has been renovated to be clean, but isn't soundproof and groans and creaks are heard at any time, day or night. Downstairs, the lobby has a huge central table surrounded by a sectional couch occupied for most of the day by hip young people with their Macbooks and dour looks on their faces. The great Stumptown coffee is served through a portal to the shop next door.
I've been once before and the service was cool and indifferent. This time, service was pleasant and deficiencies (non-working shower, etc.) were attended to quickly.
Parking is at an outdoor lot about 1/2 block from the Hotel. It's safe and convenient although I wasn't sure the first time I stayed.
The hotel is right adjacent to The Pearl district and about 1/2 block from Powell Books, a spectacular destination.
In summary, the hotel is true quirky Portland. If you want a regular stay, try elsewhere, but if you're young and hip, this is the place. Oh, it's not particularly cheap for being spartan.

Ultra cool, but surprisingly unpretentious, this is a great value-for-money option in Portland. Rooms, while on the small side, were spotless, stylish, and comfortable. Loved the Malin+Goetz toiletries, and the awesome Wings and Horns robes. Shopping is great fun in the Pearl District, topped off with a visit to Clyde Common for some great happy hour cocktails and snacks. Stumptown coffee is as superb as everyone says, and we also had a great sandwich at Kenny and Zuke's on the corner. Overall, a great few rainy days in a pretty cool town. Stay at the Ace, it's really a slice of Portland that is worth trying.

Very beautiful, detail focused hotel.
The environment is very cool and the ambient too.
Attention to detail is ver taken care of but......
Beware of multiple bills.
I went on a business trip with worldwide colleagues and to pay was HELLISH. I stayed for 3 nights and my colleague from Mexico another 3. I payed 185USD and he payed 125USD. Does this make sense? NO, they want to charge everything in one credit card and the system does not allow separate bills. So if you travel in business group choose a different option, and do not stay here.
In my case all we wanted was to pay and they were not able to find a way. The paying experience was so bad my company will never hold another event there.

Also, never stay there on friday or saturday. There is a discotheque right in front of it and the noise is just terrible until 3am

The hotel is fine, it tries too hard to be cool. It reminded me of my old dorm in San Francisco, very minimal, but honestly it is overpriced for a room with a private bath. There are better hotels to stay at in the same price range. I actually love the Ace in Palm Springs, but this one is just not as good in any way. The staff were not very helpful and, as others have stated, seem to be irritated if you need anything from them. We had one experience with a guy at the front desk that was flat out rude. I was shocked at how we were treated and talked to, not only was he really catty he was also condescending and I did not appreciate it. My fiance and I travel a lot and have stayed at all kinds of hotels and have NEVER been treated like that. Unfortunately for the Ace Hotel that employee has ruined our entire experience there and tainted what could have been a fine experience.
What I liked about the hotel:
good location, good coffee downstairs (you have to pay for it), photo booth, bed was comfortable, suites are big and roomy, free wifi
What I didn't like:
Staff has bad customer service and bad attitudes
standard room is overpriced and very small (suite is overpriced too)
bathtub/shower had weak water pressure, hard to get temp. just right
rooms are cold and have a draft in the winter heater couldn't battle the draft
lobby is always crowded with the coffee shop crowd using the couches and free wifi
Honestly the staff is the biggest problem for this hotel. I know Portland is all about the hipsters, and in that world bad service is cool, but I have to say bad service is never cool.

If the staff didn't seem completely irritated at the fact that you were there, then I might have considered it an ok place and possibly stayed there again if I just needed somewhere to crash in PDX. The staff made it such a bad experience I would never even consider it again. I'll stay at Hotel Monaco next time.

Don't waste your money, stay somewhere that appreciates your patronage and puts the money back into the rooms and services.