I can't say enough good things about the Atma-Sphere GaNFET Class D monoblocks, which have been in my system for the past four months. They have been a big part of the transformation of my listening experience.
The A-S monos replaced a pair of excellent PS Audio M700 class D monoblocks, which used the ICE modules along with some fine-tuning of the output stage to improve the musicality of those amps. For me, the M700s had earlier replaced the classic Pass-designed Adcom 555 stereo class A/B amp, which sounded smooth, but emotionally subdued in comparison to the M700s.
In comparison to the M700 ICE monos, the A-S GaNFET monos sound much more transparent and smooth in the highs and midrange. When paired with the planar-magnetic drivers in my new PS Audio FR10 speakers (acquired in January), the A-S monos have incredible synergy. Their amazing transparency and smoothness make them a perfect match for the low-distortion drivers in the FR10 speakers. This is the sound that is often described as open and transparent without harshness.
The low frequencies are also outstanding with the A-S monos, but they took a bit longer to develop in my evolving audio system. With a recent upgrade in my streaming gear to the Innuos Pulsar streamer, I am now also hearing the deepest and most natural-sounding bass I have ever heard in my home system. (Listen to Joe Morello's opening drum solo on "Take Five" from the album "Morello Standard Time" and you'll know what I'm listening to.)
Anyone who questions the musicality of GaNFET Class D should listen to the Atma-Sphere Class D matched with the right sources and speakers. The realism is amazing!