The QOS crap is software and is open source and has been available for years, and is always better on custom firmware such as tomato.
Even worst it makes heavy use of cloud crap meaning when they decide to stop supporting it or kill the cloud crap, then your router suddenly loses much of it's functionality.
I guess maybe this'll be handy for larger households of uncooperative users, where it may keep one person's torrents from clogging up another's video. But ideally those are simply solved issues of just configuring your stuff so it wouldn't do that in the first place.
Past that my experience is most issues happen outside the house, where neither this router nor any other will have any ability to fix them.