The Swissotel Berlin comes close to getting five stars, but isn't quite perfect. The hotel is in a very convenient location -- not close to the main tourist areas, but everything is easily reachable by public transportation, which is very close by. I would prefer staying in this location over any other in the city.
The room we had was very comfortable: a good size with enough closet space, clean, very comfortable bed and bedding, and a nice view of the city. The only drawback was the awkward layout of the bathroom, which made getting in and out of the shower a bit of a tight squeeze. The in-room Nespresso machine was a nice amenity.
Overall the service was good, especially the front desk staff. On the occasions we asked for a map or had questions, they were friendly, patient, and informative. The concierge present at the time was less friendly; seemed in a hurry to get rid of us.
I would definitely go back to this hotel; it was a good value for the quality, and I really liked the location.