We were there in 2001 and, while the Sheraton beats all for location, the Hilton is more modern and has far better service. The Sheraton was dark and dismal and the help would hardly speak to you. On the other hand, the Hilton employees went far out of their way to make us feel welcome. The driver of the van who took us for free to the train station actually walked us to our seats as he thought we would have problems with language. No one anywhere we have gone has been so courteous and caring. The Hilton is the favorite of the former prime minister. You can walk to the huge city park from there and cabs are cheap to downtown. There is an excellent museum up on the hill past the Hilton from town. Great views from the huge windows. There is also a museum next door which had geological displays. Be sure to see the ancient church in the middle of the main thoroughfare downtown. We also took a day trip to the mountains to see a monastery. We spent 4 days in Sofia and it was about right. Beware of the gypsy kids who will torment you and pick your pocket. More gypsies there than any other city we have been to, esp downtown.