Uploading to YouTube or Vimeo question....

I've made a couple videos using GoPro Studio (3-4 minutes each). I have saved them in several different formats, but nothing seems to work when uploading to YT or Vimeo. I mean, they work but the quality goes to crap. I can watch the same exact file on my computer or upload it to Dropbox then email it to friends and it still looks amazing, but as soon as YT gets it and compresses it, it's not worth watching...

Anybody else run into this? Do I need to use some kind of Codec or is it just not possible to make my videos look as clear as the GoPro videos on YT???

I record in 720 60fps, I do a little slow mo, real time, speed up, and add music... Nothing fancy

Any suggestions?

Ohhhh and I upgraded and bought a brand new desktop, which is specifically designed for this kind of stuff...