Nice place, but a little over hyped in my opinion, 3.5 stars
Overall a pleasant experience and a nice place to stay. But I think it's a little over rated looking at other reviews. This place is definitely above average, but I might not say Very Good, only because of a couple of critiques that might not concern others. In any case, I gave the place the benefit of the doubt and rounded up my overall rating. Would I stay there again? Yes, but only if the location was appropriate. To come stay in Seattle, I would stay in downtown. Clearly this place will be serving Amazon business, and other Paul Allen adventures in the redevelopment of South Lake Union.
My comments below may help you understand why.
Narrative of our stay.
The valet people were expedient, nice, and competent. Check-in was quick an easy, after which we found out the hotel was at 100% capacity for the evening. Not a surprise, since we were staying there for New Years Eve. Even though they were at 100 % capacity, it did not feel like it at all except for a one of failure on their part. We opted in to buy the welcome champagne bottle in the room gift. It was suppose to arrive to our room shortly after our arrival. We waited 30 minutes. Nothing, called down to Service One (their name for customer service) and they would check on it. 30 minutes later it arrived. It arrived one minute before we were going to cancel it and start our evening elsewhere. 
Room
The room (Premium King City View) was adequate. I'd say these rooms are more geared for the business traveler but not uncomfortable for the couple either. A single office chair and desk, and a day bed'ish lounger are there besides the bed. A 32-inch LCD sits on top of a short wide dresser (half is taken up with the mini-bar). Local TV channels are all non-HD, so not a big deal, but another nicety not there. Armoire plenty big, and more than enough hangers (nice wood with spring clips). Ironing board, and iron also stored in there. The windows are 3/4 full length and the whole width of the room. There are condominium buildings near by so privacy with the curtains open is minimal (feel sorry for the condo owners, although they must get good entertainment at times). 
A small 12-inch window can be opened! That is a nice feature to get fresh air. On that note, the climate control in the room is very efficient and fast. The room temperature was easily and quickly controlled.
A small electronic safe is in the room. Might be able to fit a small laptop...maybe (I forgot to check the depth of it). 
Mini bar
It's one of those magnetic ones that automatically bill you as soon as a bottle is used or MOVED. I opened the fridge door, didn't touch a thing, but at check out it said we consumed 3 mini-bar items ($7.95 an item). Clearly this happens frequently, they didn't bat an eye when we said we didn't take anything from the mini-bar. So check your bill upon checking out!
Bathroom
Nice decor with granite and tile, large soaking tub with the wall that can open up into the bedroom and still have a view to the city. All the amenities for soaps, shampoo's, conditioner, etc. Nice spa quality! Only critique is the water pressure for the sink is way too much, and not enough in the shower. The sink can spray out from the basin, so be careful if dressed up already. While the shower pressure is adequate it's not great, but that might be a personal preference. Again, the bathroom is more a 1 person bathroom in size, but not uncomfortable for 2 that are intimate with each other. The hair dryer is a REAL hair dryer so no need to bring one. The toilet is a eco friendly, with half flush and full flush option. The only thing missing (in my opinion) are Q-tips. Why hotels don't include them continually amazes me. The cost is nearly zero to provide a few per night. Also, for the air traveler, there is no toothpaste or mouthwash either. Again, in these days of 1-qt bags of liquids, I would like to see hotels start providing that as well as the shampoo. 
Complimentary coffee in the room is a good quality local brand. But if you opt for your own, the maker is the type (4-cup) that you could buy your own and filters and brew a pot. It's not the single serving type. I prefer the 4-cup type because you can bring your own grind as an option. 
Tea: NOT provided by default. You need to request it from customer service. So if you're a tea drinker, as for some tea when you check in.
The alarm clock is iphone/ipod docking station kind. BUT, if you have the "Bumper" for your iphone, it will not connect properly. You need to take it off for it to connect. 
The bed, while the beds are commissioned by the Queen of England, they are an average comfort bed, not phenomenal. The linen on the other hand is AWESOME! Pillows are fluffy down. One drawback, if you want to prop up in bed to watch some late night or morning news, the pillows are far too soft to prop up. You need to abscond some cushions from the lounge chair, which really doesn't work well. There are no extra pillows in the armoire augment. So...not comfortable to watch TV in bed. 
The view
There are a couple of rooms per floor that have a fantastic view of the Space Needle. But only a couple! The otherwise the city views are kind of typical for a Seattle hotel, except no water views at all. 
Conveniences
The hotel also provides access to a gym which is a spa/gym, and the equipment quality is fantastic along with the size. I've experienced maybe one other hotel with an equivalent. So if your a gym person, you're styling! Only critique is it's a short walk across a courtyard outside.
There is a gourmet grocery (Whole Foods) store within the same structure, so anything you may want can be bought there. A Starbucks is also in the same structure. 
I'm not really familiar with West Elm, but my girlfriend loves west elm. There is one across the street.
The lobby of the hotel has a gas fireplace with a nice setup of couches. The love seat couches are next to the fireplace are surprisingly UNcomfortable. But, the hotel bar named The Bar will serve drinks to you out there. NICE!! I have to comment on the name THE BAR. That is such an Abbot and Costello name....let's meet in the bar. Which bar? The bar. Okay, which bar? THE BAR!! It works because there are 2 bars in the place, The Bar and the Seastar bar. I digress.
There is a light rail transit just outside, the South Lake Union Transit...yes the nick name is S.L.U.T. Compliments of Paul Allen. You can even find t-shirts with such, e.g. I rode the... You do have to pay, not sure of the cost but probably a couple of bucks. 
THE BAR
Caution- cell service is No Service!! At least for ATT customers. So don't be waiting in the bar (The Bar) for someone expecting a call! You have to be almost back in the lobby/fireplace to get a signal. Otherwise, the bartenders were great, pleasant, helpful! Their choice of ambient music (unofficial music) is fantastic too. Not the elevator music one may expect.
Seastar restaurant is on premises. A great restaurant. See my separate review for that, with a couple of recommendations on menu items.
Cons
You are not conveniently located downtown. Everything starts a few blocks away and further. So if inclement weather occurs, you'll need to taxi around. If you want to stay there and walk around the town, I'd say this is not the best location. You really do feel kind of isolated from downtown. There is the light rail (mentioned above) that can take you either to Lake Union where more restaurants are located or to Westlake center the beginning of downtown city life (but Westlake Center itself is kind of marginal in my opinion). BTW, if you by a s.l.u.t. ticket, that does not work for the METRO transit, although metro transit is free downtown.
Happy travels, and happy new year!