Just tested C4K 24p, 60p, 4K 24p, 60p, FHD 60p, 120p, 200p. All in H265 10 bit HLG.
The same landscape scene, focused at infinity at F8 using a manual focus lens.
Viewing on a 27 inch 4k monitor at a viewing distance of 1 meter in full screen mode without any zooming in.
C4k 24 p and 60 p look very close, 24p might be a tiny bit punchier. If don't pixel peeping, hardly any difference to my eyes.
FHD 60p, 120p, 200p are noticeably less detailed and muddier.
C4K 60p 10 bit HLG looks fine even to the latest standard.
But none is as good as the 120p photo mode. I used art 1 filter, so the jpeg looks very colorful and punchy, but still has a good dr, much better than EM5 in art 1 mode, which has a very limited dr. The IQ of the 120p 20 mp raw plus jpg is just like, eh, the photo quality. LOL.
Somehow the mf lens can not be stabilized by OM1, almost no stabilization at all to my eyes. Big bomber to me, as I bought this OM1 to stabilize my mf lenses.