Okay, I am now a convert to 32 bit floating. Preliminary impressions, not strict comparisons or measurements.
I had used both a mixpre 6 II and a Zoom F6 for recording chamber concerts before Covid. Since I could always set levels and get enough gain from those pre-amps I didn't really find too much of an advantage from recording 32 bit v. 24 bit on these recorders or v. 24 bits on the F8n. I could always add 8-10 dB in post without much impact on the final product, and set levels conservatively.
But I also use an MMA-A plus iPhone with Metarecorder, a major drawback of this setup in some cases was the limitation of the MMA-A to 30 dB gain. With DPA 4060 mics this has never been a problem, but I also use the DPA supercardioid 4081s (with a bass boost in post) for some things, and these mics are less sensitive. For most louder things, a boost in post of 8-12 dB would be sufficient and did not spoil things; but very quiet programs like harpsichords or viols from a distance in a large hall begged for 20-30 dB additional boost in post, and that was generally ugly. I eased into feeding the iPhone from a Sonosax SX-M2D2, but using only a cautious 35-40 dB of gain the needed boost in post still didn't sound good. Since the Sonosax is a fantastic preamp A/D, I was disappointed that the necessary gain in post was still problematic. Last week I got the settings right, a total of 57 dB (20 "pre-gain" + 37) got very nice results. So today I went with a Zoom F3 alone, DPA4081s and DAD6001s to use the F3 phantom power to run the mics. The resulting 32 bit file was a distinct improvement, seems almost as good as the M2D2 with levels set correctly. YMMV, but I'm impressed with the Zoom implementation of 32 bit and look forward to the format in even slimmer machines than the F3.
Now these comparisons are only impressionistic, different groups played, different repertory. But it's in the same space and I'm in the same seat. I've had some intermittent issues with Metarecorder lately, including a complete loss tonight (I think it's a stability issue with newer iOs upgrades, happens with different MMA-A units and mics and went away with deleting and reloading Metarecorder). So I hope to try the F3 at other places, also with 4060 mics.
Jeff