We stayed at the Grand Hotel Sofia for three nights at the beginning our trip to Bulgaria and Romania. I would recommend this hotel. It is very centrally located and an easy walk to many of the main attractions. It is adjacent to a nice park which is good for people watching.
The rooms are unusually (and unnecessarily) large but very comfortable and very quiet. The bathrooms are very nice with all of the amenities one would expect in a five start hotel. I agree with the comments from other reviewers that the rooms could be on the warm side although the thermostat seemed to work to regulate the temperature on one night.
The breakfast restaurant is also very nice with a wide assortment of foods on the breakfast buffet.
The whole ambience of the hotel is rather formal/fussy but I think this may be par for the course in this part of the world. We felt like eating dinner in the hotel one night but the dining room was just too grand and formal looking and largely devoid of people. We headed out for a walk and found a small bistro just near the hotel (see my view of same).
Again, I would stay again on a return visit to Sofia.More