Ace Hotel in Seattle is, in comparison to the one in NYC, very small and very bright. But still, very modern, tasteful and with a very helpful staff. I stayed in a double (w/ our own bathroom) with my mother. The room (121) was facing the water and had a TV, couch, desk + chair and a queen size bed. Since I am not one to hang out in the hotel room when traveling, I was pleased with my stay! The bed was really comfortable, the room clean and there was a snack bar if we had the munchies. A bonus also for coffee and tea that is always available in the breakfast room.
Breakfast was definitely OK, but I am Swedish which means I am used to more savory stuff. Here, it consists of a belgian waffle with maple syrup, sweet yogurt, bread, granola, fruit, coffee/tea. Simple but tasty, although we chose to have breakfast out of the hotel two of our three mornings.
Location wise it is very close to downtown and the space needle, but if you like the more vivid nightlife aspect of Capitol Hill, I advice you find a hotel around there. Having said that, I do think that Belltown is up-and-coming and I would definitely recommend the hotel to friends.