I saw a CNN report on these parties over the holidays. Basicly they said that most companies that buy gold at parties give you an okay price, but not the best you can usually do on your own with a bit of leg work. They recomended taking it to several different pawn shops and jewelry stores, and see what others are offering.
But, if you don't feel like doing all that, or there aren't many places that buy gold in your area, you could do worse than a gold party, at least according to the report. In your shoes, I'd get the name of the company buying the gold ahead of time and doing a bit of reserch on them, just to make sure there aren't any known issues with them.