That's kind a a tough one. Keybed feel is like keyboard sound. It is so subjective from one person to the next. So I will just state my impressions and try not to sound like I am postulating any absolutes.
The day I tried out the MOX6, I had gone there specifically to get the Roland Juno-Gi. I was really after that plethora of acoustic and electric piano voices in the Gi, but wanted to look at the MOX6, in case I didn't like the Gi after all. For many years, I have played keyboards of all different values and have become quite tolerant of keybed feel, but keybed feel was the first thing I noticed when comparing the Gi with the MOX. The MOX feel was not what I would have expected from a $1200 keyboard and was not on par with the $900 Gi. It was not "bad", and would not have kept me from buying the board, but it just was not what I expected. You mention the JV-30. I had a JV-80 for many years and wish I still had it, but I don't think the JV-30's keybed was on par with the JV-80, and my impression of the MOX was that its keybed is not on par with the JV-80, but this may be an unfair comparison. I truly believe that design and production investment and quality control in keybeds was far better in the JV-80's era than today. Now, as far as overall, if I had the money and the room, I would have the MOX6 right here in the studio right now. I would love to have access to those XS sounds without the investment in funds and weight and size of a full blown XS6 or XF6.
Hope the helps. Good luck on your choice.