I'm not a digital amp expert but I believe they are mostly class D amplifiers. They run much cooler than traditional A/B amps, provide more wpc without being strained, and are more efficient. I do belive that the digital amps will be taking a larger market share as time goes on. Here is a short article on digital amps:

http://www.elecdesign.com/Articles/I...ArticleID=3802

Hope this helps as the digital world encroaches on us all.