I stayed at the Ace Hotel over Christmas. Because business was slow, I got a free upgrade to a better room without even asking. That was nice! The room itself was fairly spacious, clean and comfortable, but the comfort level suffers a bit from the building's past as the low-rent Clyde Hotel (before the Ace people bought and renovated it). The single-pane windows let in drafts, and that means the heater is constantly going on and off to compensate. Also, the tiled bathroom is unheated and can be pretty cold in a Portland winter, but it's probably really nice in the summer. I liked the comforter topped with a Pendleton blanket -- that was a nice Portland touch -- and the iPod compatible alarm-radio would've been great if the iPod hookup had actually worked. Fortunately, Portland has some great radio stations, and the Ace has tons of cable channels.
The only real reservation I have about the place concerns a lack of security. Quite often, I'd come into the lobby at night and there would be no one at the front desk, which means that anyone could walk in off the street and go upstairs into the hallways whether they were staying at the hotel or not. Portland is fairly safe, but no city is free from crime altogether, and the situation made me a bit uneasy.
More positives: The food available at all three eating places within the hotel is excellent. Stumptown Coffee isn't my favorite, but they've got excellent pastries, Kenny and Zuke's is an excellent deli, and Clyde Common has an awesome bar and quite good food. All in all, the Ace is a fine place to stay even though they could do a little better with the security situation, maybe finding some way to limit access to the upper floors and elevator without compromising the funky character of the hotel.