Digital technology has come a long way in recent years. "Digital", i.e. switching amps do a pretty good job when operated at full-scale output. They are also great in terms of efficiency, often weigh less for the same power, are simpler to design, and cheaper to make. Great! So - where's the catch?
The problem with music is that it is not a constant sine wave. In fact, the better a recording - the higher its peak-to-average ratio. When amplifying musical signals without clipping, an amplifier will be operating at an average power way below its peak rating. Furthermore, it is only on rare occasions that the full power output is utilized.
At lower than maximum output, digital equipment typically has a rising distortion, as one bit is lost with every 6dB down. It may also produce "digital artifacts" - new sounds not present in the source material are created through the very principle of operation. These side effects increase in proportion to the signal as the amplitude decreases.
Analog circuits do not have this fundamental problem - distortion falls off with amplitude. They have superior sonic fidelity and resolution. When carefully designed, overall efficiency need not be sacrificed. Last, but not least, analog circuits come closer to representing real-world events. Also, they are a lot more challenging to design and we really enjoy building them!