I'm having similar stuttering issues with Channels. Love the app, but trying to get rid of my cable package and using Channels with OTA and HDHomeRun Premium channels. I have an HDHomeRun Extend.
I'm currently having issues watching Monday Night Football on ESPN. It stops and then starts every 2 to 3 seconds. When I ran the speedtest, I got a few results below...
Download - 59.63 Mbit/s
Latency - 18.59 ms
Jitter - 6.65 ms
Download - 58.51Mbit/s
Latency - 15.97 ms
Jitter - 5.53 ms
Download - 56.64 Mbit/s
Latency - 14.76 ms
Jitter - 6.08 ms