The NHL channel is working very well and all the archived games I have looked at play fine and the vast majority are in 16x9 format and many, if not most, are HD.
The games in 16x6 format WILL be letterboxed on a 4x3 screen as that is the correct way to display those so you do not loose the edges. And we all know how bad it is to loose an edge in the NHL.
The live games, watched live, sometimes give me a bit of buffering issues but I have found if I choose "Watch from the beginning" I have less issues and it is pretty quick to FF to a point close to actual live if I so desire but I usually start a game after it has been going for 30-45 minutes and skip the commercial interruptions with the right arrow. (Pressing right about 8 times skips most of the regular breaks) I also skip the period breaks by FF (x3) about 15 minutes from the time bar. By the end of the game I am usually only about 5-6 minutes behind the "real" live point.
There were some early problems when the NHL released a beta version of the ch but they have now released an upgrade to that and most of the problems are gone.
Occasionally there will be issues with the ch or a specific game's feed but, so far, they either cleared up after a while or they are easily traced to internet/feed/encoding problems.
All in all the NHL ch is one of the most pleasurable chs to use, but it ain't perfect.