Ambassador was a nice hotel, excellently situated (middle of Vaclavske Namesti ).
Breakfast was very good, staff were all friendly. BUT the price was high for what the hotel offers (eg no gym) - although it has a 5-star rating, 4 stars would be more appropriate.
More or less part of the hotel are the Ambassador casino (open 24x7) and the Goldfingers strip bar (said to be Prague's most upscale)