There are better options in San Francisco
I travel to SF regularly on business and have stayed at several of the SF hotels. In reading other reviews of the Adagio, it's my observation that many who gave it four stars in fact have complaints that warrant a lower grade, especially given the hotel's so-called "luxury" category, the apparently misleading photographs published the hotel, and other details mentioned in the prior reviews. Here is a run-down of my pluses and minuses about this hotel.
I arrived at about 8:30 p.m. with a guaranteed reservation. The front doors are not automatic and are quite heavy -- not a big deal, but there is no one standing outside to give you a hand, as is the case at other "luxury" hotels. Once I got myself and my luggar through the door, the person who checked me in was nice enough and offered me a bottle of wine delivered to the room, given my Joie de Vivre membership. He then informed me -- and JDV members take note -- that the hotel will be leaving the JDV membership in February. The room, which was an upgrade, was a corner room on a high floor, with very pretty decor. The bathroom, however, was clean but had none of the modern fixtures you would often see in hotels of this price level. The air conditioning unit was connected to a fat tube that ran out the window.
Actually, all of the forgoing stuff did not bother me that much -- but did bother some of my fellow business travelers who have similarly found better accommmodations in SF. My own biggest criticisms were two: (1) the hotel gym is really sub-standard. There are a handful of cardio machines, but all are outdated. They do not have Precor machines, which are pretty ubiquitous in hotels of this caliber (especially in California) these days. There are also no yoga / stretching mats, and (2) I think the concierge service is also pretty weak. Note the comments from people below who were directed to bars that had stopped serving and restaurants that had closed. I similarly had an unhelpful discussion with hotel staff when I mentioned that one of my favorite SF restaurants was just up the street and asked if he knew whether they would do a delivery or carry - out. He did not know and then told _me_ to tell him if I found out anything (i.e., rather than offer to try to find out and/or arrange something).
A sharp contrast to the typical luxury hotel where you practically have to tell the bell staff to leave you alone. There is complimentary coffee in the lobby in the a.m., but the cups are ridiculously small. This is a tiny detail, but I think it is, in some ways, a microcosm of what's wrong with this property. They are _not_ trying to exceed expectations, but to just "meet" them and be "good enough," perhaps relying on their great location. Particularly with experienced travelers, I think this minimalistic approach is going to lead to disappointments.
I sincerely hope that, once the hotel leaves the JDV membership, it is picked by some sort of umbrella organization that makes some approvements, starting immediately with the gym equipment, which would not be a small investment, and the coffee cups downstairs, which would be a miniscule investment. And then having someone stationed outside (like a "normal" luxury hotel.) 
A note to those unfamiliar with San Francisco: The hotel _is_ just off Union Square and is also well located for the theater district. But keep in mind that SF is very small, and there are tons of hotels that are within a ten to fifteen minute walk of Union Square. 
I really do hope the hotel improves. It's a very pretty building and its location are excellent. But, in the meantime, I would look elsewhere. If you are looking for budget business travel, check out the Courtyard Marriott on Second St., and if you are looking for luxury or deluxe business, check out the Omni.