Class designs? A, B, AB, C, D, etc.

[Drew664]

I'll just say I read the wiki on these designs, and it went right over my head. What I'd like to know is in layman terms, how each amp build effects sound, efficiency, and the build itself.

The spur behind this thought is the big monster that Emotiva is brewing. A 400w x 7 class H amp. Why class H? What's the difference between these builds? Is there a class that tends to perform better for music or HT?

If anyone could shed some light on this, it'd be appreciated. All of my Google searching has resulted in over technical answers.