The ones where you (usually) won't see complaints are the Cheersport and NCA ones. Cheersport isn't technically a live feed, but they're really quick with uploading high-quality videos, and NCA definitely learned from their mistakes 2 years ago (especially not starting exactly on time) and I can't remember any complaints this year.
And I didn't have problems for the majority of the worlds weekend either, but according to King that had more to do with the fact that I'm in Europe than anything else. So I'd only recommend the worlds feed if you're outside of North America. On the other hand, watching the vod for worlds gets you through the summer, so people should at least get the vod.
But unless some major things change, I'd never get the CheerLive feed. Their feeds are always choppy and I haven't heard one good thing about their customer service. The other ones though - totally worth their money!