class A/AB vs class D / H amplifiers

I've been reading more about solid state class A/AB audio amplifiers vs the newer class D amplifiers. I find it interesting but not surprising that many class A/AB owners dismiss class D as a fad and "not musical." And then you have the class D or H owners who will tout significant power efficiencies and think class A/AB owners are foolish to spend large amounts of money for 100+lb amps that generate a ton of heat for sound quality that no doubt is great but is not much better than newer class Ds. For the record, I am a class H owner (Sunfire Cinema Grand). And I really like my amp. Clean, dynamic, dead silent and runs stone cold. No matter how much I crank it up or when there are transients, it doesn't break a sweat or lose it's finesse or poise. It is a gentle giant. I've even considered getting a 2nd amp used on Audiogon for 7.1 purposes but it's not something I am itching for right now.

But still, I have that curiosity. While I really enjoy the benefits of class H, could there be some appreciable element(s) of Class A/AB that I am missing out on? Right now, I'm not really qualified to have an opinion since I've haven't done any listening comparisons. Being value oriented, I have always been skeptical of the higher cost class A/AB amps from Krell, Classe, Plinius, Simaudio, etc. But through numerous discussions with one of my coworkers (who happens to be a die-hard tube amp fanatic but likes a few solid states), I've learned of smaller class A/AB outfits like Odyssey who are getting a lot of praise from end users for their price/performance. Another class A/AB company that I'm interested in is Gemstone Audio. Gemstone seems to be somewhat similar in terms of business model to other internet "bang-for-the-buck" Mfg'ers like Outlaw Audio and Emotiva. Anyways, even though I am still skeptical about the boutique brands, I think it's best to keep an open mind. The question I always ask myself is why do certain "high-end" amps cost significantly more than others? Is it mostly marketing? Placebo? OTOH, market forces are at work here. Enough people are buying the Krells, Classe's etc to keep them in business so they are obviously doing something right. Whatever the case, I am fascinated by engineering design choices and understanding how a Mfg'er allocates the budget toward a product (ie how much of it is actually toward the actual circuit design or components or power supply or chassis, etc.....or is it more toward a fancy chassis? Perhaps marketing costs? Or does it also have to do with economies of scale/size of the Mfg'er?). I don't think it will be easy to find the answers to these questions.

Back to A/AB vs D vs H - I suspect it will just boil down to a lot of listening and testing myself to see if I can hear a difference between A/AB vs D and figuring out my own point of diminishing returns.