If you go straight through an HDMI cord, there's no noticeable degradation. Streaming through something like ChromeCast or a similar wireless device, it's all dependent on how good your wireless signal is. On my old COmcast Xfinity setup, the wireless signal was great and there was no noticeable lag (unless my wife or stepson started streaming something/downloading/etc.). Now that I'm on a DSL connection, my WiFi sucks and it's not an option any longer. HDMI still works, but that's annoying.
Hockey Streams also has a Roku channel, for those who use Roku.
For me, it has been the opposite--GCL was always 45-90 seconds behind, and Hockey Streams was about 5 seconds behind. HS advertises a really low latency; I think most people experience what I do. That's the thing with anything web-based, though. It's all variable depending on your location, connection, etc.