This boils down to preference, there isn’t a whole lot of evidence that WASAPI is better than DirectSound from an audio quality perspective. The main difference is that DirectSound will always use the Windows mixer, so you can tack on additional things to your sound chain, like having an external DSP (like DFX / FXSound) or a system-wide equalizer application (Equalizer Pro, Equalizer APO).
When you use WASAPI, however, it completely bypasses the Windows mixer. This means audio output will be sent directly through your USB audio interface from your computer, and you cannot use any external DSP / Equalizer outside of the media player you are using.