Cerrot, respectfully, I can't disagree more. While tube, solid state, hybrid, and switching, amplifiers may have differences in their presentation, even in their own categories, your statement is simply to broad.
Many people who have tried switching amplifiers without taking proper steps to integrate them into their systems have had some issues with RF and VAC supply to the amplifier. These problems were audible and directly limited their performance. Pioneer has taken many of these issues seriously and, for the most part, remedied them. I've owned three different switching amplifiers as well as tube and solid state. The Pioneer receiver is the first switching amplifier that was simply plug and play. It's unusual captive two prong VAC cable / plug is an obvious design element.
In my comment above I cite my actual experience with two different designs that I have lived with. Some years ago in my auditions of the Integra, Denon, Marantz, NAD, Sony, and Arcam, receivers I compared their sonic as well as their build qualities for use in a modest HT system. I was fortunate to audition the Integra, Denon/Marantz, and the Arcam, at the same location using the same system.
Sonically the Arcam had the nicest upper midrange to highs of the bunch. Looking inside all of these units the Arcam had excellent build quality yet it ran hot and lacked, some bass punch, and was seriously lacking in HT features.
The Sony had good bass, up to date features but had little in the way of finesse in the mids and highs, a sort of flat presentation.
I was unable to directly compare the NAD. It's build quality was good and it was pleasant to listen to.
The Denon/Mrantz for all intents and purposes are the same build with some minor differences. Along with the Arcam I was able to compare them with the Integra in the same system. The Arcam and the Integra clearly had a better selection of parts. Since both the Arcam and the Integra had a better overall sonic presentation and could play louder with less fatigue my choice between the Arcam and the Integra was made simple by the Arcam's shortcomings. The Intgra didn't just edge out the Denon/Mrantz it was flat out a better receiver.
While I can't speak of the latest offerings of the receivers I've mentioned above I will say the ICE powered switching amplifier section of the current Pioneer SC receivers is a huge improvement in HT receiver format audio. Since each channel essentially has its own power supply there is no need to suck power off of a shared transformer. This will become stunningly apparent to the ICE receiver owner when they listen to a film at theater like levels. The absence of fatigue will amaze you at just how loud the thing is actually playing. My Integra, which could easily out preform the other linear solid state amplifiers I auditioned, simply could not play this loud without breaking up or distorting.
At lower levels the Pioneer's all important midrange simply sounds more liquid than it did with the Integra. Since my system is crossed over at 80Hz to a subwoofer, bass is not an issue in my system. Keep in mind switching amplifiers have been used in subwoofers for many years. Their bass reproduction is is almost unparalleled, if at all.
Cerrot mentions, "yet" in regard to switching amplifiers. I would somewhat agree with that. Switching amplifier's have only recently come into their own with the advent of faster processors which now do the switching at a very high bandwidth. Along with RF and circuit improvements these designs are evolving rapidly. Pioneer has used many of these improvement as well as some of their own in this their first generation switching amplified receiver.
Other advantages to a switching amplifier is their electrical efficiency. They use power on demand through a more efficient power supply which is why they run very cool, take up less space, and use less wall voltage, compared to traditional tube or solid state designs. Lets face it these things are on for long periods of time.
