When the Z9 hit the market, I had the opportunity to test one of the "merry go round" units... back then I was shooting the D6`s and the D500. I must say I didn't appreciate it much, specially because of the (apparent) noise compared to the D6 (and the occasional freezing...).
I bought one anyway, thinking "I have to have one"... but I always hoped it could have been just a 24Mpx...
Then, the various FW upgrades were made available (I'm still on 4.10) and I (think) learned along the way how to deal with the massive 47Mpx... today, I have 2x Z9's and still holding the 2x D6's (the D500 is tucked away), I wouldn't go back to 24Mpx, couldn't think why would it be any better but hey, let's wait for Steve to tell us what he finds out. Regardless, to me, the grip is a "must have" thing so no, I doubt I'll jump for one right off...