Get a tape from the band or make your own so you can compare and contrast as you make the decision on a band.
The best bands and Djs always ask for a list of preferences. They will want to know what songs to sing or what bands to play. The music makers want to know what songs you want to play during the reception and what ethnic numbers and favourite songs the guests are guaranteed to dance to. Most important, they should ask what not to play.
Ask the band or the Dj to adhere to a dress code dictated by the theme of the reception