Class-D or switching amps, any opinions on??

Here are some interesting links:
The International Rectifier module has a fullbridge / halfbridge selector switch for those who can't decide!

https://ec.irf.com/v6/en/US/adirect/ir;jsessionid=74D07C3679B3902FCD3E847F05518E49?cmd=catSearchFrame&domSendTo=byID&domProductQueryName=IRAUDAMP7S

Here is another link with several articles on 'd' amps.

http://www.irf.com/product-info/audio/classddesign.html

I have the IR reference board out in the garage, awaiting a power supply. I will be able to directly compare with an ICE moduled PS Audio GCC integrated, which I will probably be forced to use as a preamp! Awaiting funds to build a +-55volt ps.

Dob - Sinclair produces class D audio amplifier called X-10 in 1964 (Designer: Gordon Edge)

That is one of the best descriptions I've yet heard. Class A is more like meat and potatoes where as class D is more like sushi. Nice analogy Jax!

I have been using the Tact digital amps for sometime. The lower noise floor has allowed me to understand words in familiar songs which had been previously buried in the mix while using tubes and class a/b solid state. I interchanged the Tact with my CJ 2500A and my ARC vs55 for a few weeks, but finally I could no longer tolerate the additional noise in the analog amps. Nothing is perfect, but digital amps now offer lower noise and greater resolution than analog, and they can tailor their response curves and loudness contours to taste (and speaker demands) with no additional distortion penalty. It can only get better!

Probably not the only person here who has owned class A, A/B, D and tubes. Currently using two PS Audio Trio C-100 in full balabnced bi-amp configuration. The C-100s use the same ICE module as Bel Canto, Cary, Rotel and probably many other makers use. To my ears they are exceptional for the money.
I won't say they beat the others in every category. But for many reasons, including the low power requirements and small size, I'll stick with them. When the newer ICE versions hit the used market I'll probably move up in power, although in my small system, 100 watts bi-amped is probably sufficient.
As stated earlier, your ears are what matters. At used prices though, if you are really curios, give one a try.