I thought the choice was going to be between something more difficult like raw sexual attraction vs engaging & intellectually stimulating conversation in a long-term relationship.
Transducers seem to be where the biggest challenges lie and most distortions occur (or where the voodoo happens, depending on your metaphysical persuasions) and so usually deliver the biggest audible return on investment. Mics, phono-cartridges, headphones & speakers are the direct connections between the physical vibrations we sense as sound and the electrical world of voltages and currents. Those are also the mechanical parts of the chain and so are more costly to produce than parts which benefit from miniaturization and Moore's Law cost savings.
Following that line of thought, the transformation from the electrical world of voltages and currents to the conceptual world of digital numeric values is another radical transformation. I'd list ADCs and DACs as next in line after physical transducers. The amplification and digital storage parts are important to get right too, but pose less problems.