HAP performance with d3 seems to be on par with DXV, and HAP seems to have a lot more momentum right now as the GPU-oriented codec of choice with good support across a variety of products. Different d3 ops seem to have different preferences on deliverables, so ultimately we deliver what we are asked for.
One thing I'd call out about all of these GPU-texture-based codecs is their tendency to exaggerate banding; we've had to do some pretty aggressive debanding prior to render to keep things looking lovely.