HDR... well, not really in my opinion. To me, the image looks far too hard, as if you were actually near the nebulosity you would slam into it like a brick wall. It looks rigid, far too defined, rather than billowing and flowing.
As I said, a shame, as the Subaru data is usually exceptional, and Rob's processing is usually top notch. This one looks like an amateur discovering deconvolution and sharpening for the first time (we have all been there
)
Whilst Rick's and Mario's M78's may lack the extreme depth of the Subaru data, I feel both Rick's and Mario's M78 renditions to be vastly superior in terms of aesthetics and realistic representation.