Have had issues since mid-Dec. Used to work wonderfully but has been terrible. I have 20+ download, but have been getting buffering, start/stop, no HD, etc. Also have AppleTV - same issue. May be NHL GCL issue - perhaps its oversubscribed? Stinks
I have had virtually no problems since the first week of the season.
The only thing that I do that may be different from others is I virtually never choose "Watch Live" rather I choose watch from beginning when a game is still live.
Usually I start a game 45 minutes to an hour after the start and use the right arrow 8-9 times to skip the breaks and use ffx2 to skip forward 15 minutes to skip the between period sections.
Of course one of the teams I follow is generally "Not available in your area" so I usually watch those the next morning. (I used to record them but I find that the quality on the Roku is vastly superior to the free cable I get with my rent.) When I watch these I have to complement the NHL as they have edited out virtually all the breaks for me.
Some of the issues with NHL rebuffering could be due to similar issues as with NetFlix. One of the fixes that are recommended to try for NetFlix is to switch DNS servers in the router to Google ( 18.104.22.168 ) or OpenDNS ( 22.214.171.124 ) You might give that a try to see if helps. So far I have seen no reports that a different DNS actually helped the NHL but it can't hurt to try as you can always change it back. I also have seen no reports that it did not help.