If they could possibly implement the P4 amp section with a switchable USB to battery power (external or internal pack) it would be even better.
The USB-powered amp section is limited by voltage....which would also limit portability if you wanted to use it as just an amp without the PC
The DAC section should be superior to any other portable DAC/Amp combo. To quote:
"The SABRE32 Reference audio DAC series is the world’s highest performance 32-bit audio DAC solution targeted for consumer applications such as Blu-ray player, audio pre-amplifier, A/V receiver and professional applications such as recording systems, mixer consoles and digital audio workstations. With ESS patented 32-bit Hyperstream™ DAC architecture and Time Domain Jitter Eliminator, the SABRE32 Reference Stereo DAC delivers an unprecedented DNR of up to 135dB and THD+N of -120dB, the industry’s highest performance level that will satisfy the most demanding audio enthusiasts."