Diamond Dan DJ'd my wedding reception. I had heard great things about them, and while i won't say I'm unimpressed, I did feel that they didn't keep in contact with me as much as I had hoped. It took a few songs for the DJ to catch on to what the crowd liked, but after he did, he did a great job. Also kept the reception moving along and gave good advice as to when we should proceed with the cake cutting, etc.
PROS: Price, expertise, music selection.
CONS: Slow to recognize what the crowd liked.