For its size it is absolutely amazing, but using it for a small cocktail party is surely out of question. It produces a very good sound on a sufficient level if you play for yourself with no other people talking in the room.
For small parties I can recommend the Bose Sounddock Portable, which is bigger, but still weighs 5 pounds only. You find these Bose products in consumer electronic markets, not in music stores.
For neutral, non-colored sound the best choice would be a studio monitor such as the small Genelec 6010 or 8010 (expensive).