Why are expensive motherboards better?

I don't know much about motherboards, so this has always been a question of mine. What makes expensive motherboards so much better than cheaper ones? What do expensive boards have (besides possibly an extra PCIe x16 slot) that makes consumers want them? Here's my board (haven't used it yet; Christmas build) but I don't see any differences compared to this board (also ASRock, AM3, 1 PCIe x16), yet it's 50% more expensive. Please inform me if you have time, because it has bugged me that people choose 100 dollar boards that they could literally get for $60. Thanks for your time guys, -Jeff