I've been sticking with H264 for now - primarily because my Raspberry PI doesn't support hardware decoding of H265, so framerate is poor for those. At some point I'll upgrade the PI as the latest ones do support H265 decoding in hardware.

I didn't know the latest Pi did H265. That's quite impressive. Bet it runs hot. My laptop has an 8th gen i5 and seems to support H265 recording. I tried a section from "Life on earth" which was very impressive until it got busy with a flock of birds taking off. Then it was terrible: all blurred with blocky artefacts. I imagine it would do better transcoding a video where it isn't working on the fly.