What has been rather irritating for those of us who spent money and time trying to get NgAgo to work (for us, in the mouse), was the rather cavalier and, in some cases, condescending comments from Han himself. I would have expected more collegial dialogue and a quest to iron out any variances in procedure etc. What ever the nuance is with NgAgo and genome editing, I think it is reasonably safe to say that it will not supersede the ease in which CRISPR-Cas9 edits genomes.

Dong Liu's team was not discouraged by the detractors in their pursuit of science. Even though they didn't see cleavage activity, instead of throwing in the towel and throwing up their hands, they looked deeper and their curious minds uncovered something interesting. Their results unmistakably verified a key characteristic of the Han NgAgo+gDNA system in zebrafish: PAM-free precise gene targeting with ssDNA guides up to 24nt in length. That was a major step forward.

Han claims that he has successfully replicated his experiments twice or more with commercially available cells. Patience is a virtue. Let's give him a bit more time.

Well said. In particular the last few sentences.
"Rivers know this: there is no hurry. We shall get there some day."
A.A. Milne, Winnie-the-Pooh