Great TR. I've been fortunate to fly both on TPAC flights (NH x1, JL x2) and I agree with your assessment basically on everything.

The one area of difference you didn't note is on the whisky front. NH offers Hibiki 21 in F (and 17 in J) whereas JL is 17 in F and NAS in J. I actually prefer the 17 so it's not an issue but for a whisky person, NH gets the slight advantage.

I probably have a slight preference for NH (I like the blue color scheme, the FAs seem a bit friendlier towards me as a white American vs. the JL FAs who were very professional but seemed a bit more reserved towards me,) but at the end of the day would happily fly either in J or F (actually really like JL J well with the APEX suites - though NH with the Hibiki 17 as noted above gets a big win in the alcohol category for J).