Yeah, modern MOSFETs are just great.GaN, or gallium nitride-based semiconductors, are neither a miracle technology nor anything new. It is simply the next stage of development after silicon-based semiconductors, with improved energy efficiency at high switching frequencies, especially at high power levels. GaN cannot be used effectively in conventional analog amplifiers.
And so far, it offers no advantage in audio amplifiers, except in switching power supplies.
Current GaN amplifiers are easily outperformed by non-GaN-based amplifiers, and they are also in a similar price range.
There is no reason to expect significant energy savings when using GaN in the power amplifiers, as the average power in real music is much lower, and the theoretically improved energy efficiency at this point will be well below 10%. Therefore, the effective energy savings achieved by GaN in power amplifiers will be in the single-digit watt range.
In addition, Infineon amplifier technology has had limitations for several generations, especially in terms of load dependence, especially at 4 ohms. GaN does not change this.
Here is a small blog post from IcePower showing their own findings with GaN:
IcePower Blog Post "Is GaN worth it?"
TLDR: depends, you high is your idle power draw bill from your amps? And how long until the lower idle draw offsets the higher amp cost? For most home users, classic MOSFET based is just fine.