As a trial I've worked through an example here of uploading a sample video to the site. Initially it shows a placeholder while it renders (the video file which was HD quality and 2:30 long took about 5 minutes to render and to create an automatic caption file).
Once uploading starts you can add the video to either a group or a channel or both. This means a video can belong to multiple different places - which will complicate things for people - but that said, you can just allocate it to one channel and being able to put it in many places does give a lot of flexibility.
When you edit the video you can add text (which is searchable - but that is way less important because now all the audio is transcribed and can be searched) to describe it.
You can set who can see it - in this case I have added it to a particular channel to make it easier for people to discover, but I've also set it so anyone can see it - so if they find it in a search they don't need to know the channel to look in - this is a big improvement on 365 Video.
The autogeneration of a caption file is a really big deal - see below. I had to do nothing to make that happen.
Similarly to 365 Video you can share the video but not outside the organisation - either by copying an address to it, or embedding it in a web page.
The resulting video is well rendered and plays well on mobile devices as well as the web. The transcription is not perfect - it certainly captures most of what I said in the video but quite a few words are changed. That said, this was instant and importantly...