I think what some of the problem with CNC heads are most of the mass produced stuff is its more of a shine job than a real performance head.

No way would I hand port w9s or w8s but my CNC stuff all gets some hand finish work

Just valve job and blend can kill a good CNC port if done wrong.

I have updated some HAND PORT w9s and port to port before we recut them did not look bad but after you can see how far off hand port stuff can be.

Here is some pictures of bad a$$ CNC WORK. (Note valve job blend not done)
This is TRD cup head cut in house by Toyota.