Thank you for all that took the time to reply. I appreciate it.
I know I wasn't specific and was probably confusing as well. What I meant by 'traditional' was anything that is not GaN FET based. I should probably ask an additional question. Besides GaN FET class D amps, are there many other class D types out there?
I should probably have stated up front that I know almost nothing about class D amps other than they typically seem to be smaller than class A/B and class A amps, they are considered to be more efficient and because of that typically don't get as hot as those other two classes, and some might say that they have less "body" to the sound or can sound lean. I'm not saying that those are fair assessments. They are just general statements. I've heard some cheap class D amps and they can sound cheap, but not always. I've heard some better class D amps (4 figures+) that have sounded very good. I haven't gotten to A/B compare any against class A or class A/B, nor have I been able to compare GaN FET based class D amps against non-GaN FET based class D amps.
I guess one of the reasons that I asked the question in the first place is that what I'm hearing about GaN FET based amps makes it sound like it's a better technology, but better how? In what tangible way? Does it improve the sound (I know that's a loaded question - sorry). Basically I'm trying to understand what all of the fuss is about. I'm not trying to bash any particular technology. I'm just trying to understand.
Thank you.
I'll be sure to check out all of those links. 
Again, thank you to everyone for adding to the discussion.