A lot of this solution depends on the requirements i.e.
size of media, type of media, process to serve the media, caching and flushing strategy, design to store in DAM, your AEM's architecture to store the media, replicate the media (binary or binaryless way) to publish servers, authoring aspects, ACLs etc.
You may also need to think about other integrations, possible assets maintenance/reporting/workflows aspects etc..
Per my knowledge, Scene7 is more than just a media hosting solution. I assume that you have a solution for other use cases that may/may not be managed in AEM OOB.
If you talk about just hosting & rendering media then one of the solutions that I have seen is creating a cookieless (static) sub-domain to speed up the rendering process. In addition to that domain sharding or proxy/reverse proxy may be used before CDN to get the maximum benefit.
