Hmm, had completely overlooked it between all the information that Amazon shows. But here it is indeed. Thanks a lot!!
I "think" the C500 looks pretty good:
Indeed both H264 and H265 are supported.
The AAC audio format is also very useful because Kevin once mentioned (here) that our browsers can play it. So the Node-RED flow can capture an RTSP stream from the camera with ffmpeg, and we don't need to re-encode it because the browser - where our dashboard is running - can play the AAC audio without problems. And not having to re-encode will consume MUCH less system resources of our Raspberry.
Have been watching another C500/C800 review (on youtube) from "The Hook Up", who has very good reviews. He indicates that both cams are good. The C500 is particular good to show colors in the night, but unfortunately not that good at night IR video:
