dTube does not have:
- CDN servers in all countries and that's why it is slower
- video size optimization and file is larger
- various sizes of video streams
And if we combine all those things then it does not work for some users and is too slow for others.
It sucks do download almost ~400MiB full quality file with 10 minutes of video that on youtube is equal to 1 hour of video.
IMHO dTube is still too far from production ready video service.