There are many different ways to implement a DAC. Personally, I think that Sony is just using a "different" rather than "better" way of doing something that is not all that complicated in the first place. The mulit-level whatever sounds like marketing for marketing's sake.

Many if not most DACs these days use "1 bit" technology which is essentially converting the PCM bitstream to Delta-Sigma modulation for conversion to analog. Delta-Sigma technology has been around for decades. This is essentailly the same technology as used in SACD, except that the bitstream is stored in native format rathen than PCM on the disk.

This type of DAC has the advantage of simplicity, stable performance, and accuracy for relatively low cost. The traditional R/2R type of DAC is also very simple in concept, however it is expensive to make one with exceptional precision because the resistive ladder values must be very precise and stable - something that is extremely difficult to do when temperature changes are thrown into the mix.

So anyway, while I am sure that Sony's implementation is just fine and dandy, I also think that Sony as a company tends to do things their own way even if it means that their solution is more complicated and no better than a traditional soluton that's realized well. But then, there's no marketing value in that, is there?