The Monaco might be a little bit of an acquired taste; as with other hotels of this type, it's over-designed and seems sometimes a little more concerned with appearances than comfort. As an example, while the rooms are interior-designed to the hilt, the quality of the towels and other linens are just okay for this price point.
I will say the service at the front desk is quite good. The hotel was fully booked during my stay, but after one night in an unsuitable room, they changed me to a much better room. You do need to be very careful with room selection in this hotel, however. The building was not originally built to be a hotel, and so some of the room locations are awkward. For reasons I cannot fathom, they have guest rooms in the basement; I did not have one, but a friend did and said it was awful. I was on the first floor initially, in a room with two double beds. The room looked onto the interior courtyard, and by "looked on" I mean there were tables and chairs for the hotel's on the patio a foot from my window. Luckily it was too chilly for patrons to spill outside, but I imagine in the summer this would be a real issue. The room was also located all the way around the building from the lobby, requiring a rather long walk half-way around the whole building to reach my room. I was moved, however, to a much better room on the fourth (top) floor with a king bed. It was quiet, it was comfortable, and the amenities were fine.
The only other service quibble, which I did mention to the front desk, was that two out of three mornings I had housekeeping knocking on my door at 8:30am. This seems a bit on the early side. The first morning, I can't really fault them, because I'd forgotten to put a do-not-disturb out. But the second morning, it was not only 8:30am, but the do-not-disturb sign was also out. I still got a knock and a housekeeper starting to enter the room as I woke up. That was unacceptable. The front desk was apologetic, but of course the damage was done. And on the other housecleaning tip, I found two long dark hairs when I moved into my room, one on the bathroom floor and one on the bed. Suffice to say I do not have long dark hair.
I will likely return to the Monaco since I travel to DC frequently for work and it's close to my hotel (and it's close to some nice restaurants and bars as well). But that's not saying as much as it could, because a big part of my return visit is that the Monaco is better than the other hotels in close proximity...it might not otherwise be my first choice, mostly because of the strange arrangements of the rooms themselves. But the hotel is attractive and pretty clean, a reasonable value for the quality, well-located, with nice and accommodating staff.