Jan Gustafsson eloquently entertains and educates with hilarious off the cuff observations, in English or German, whilst also commenting with deep analytical insights into blitz games that he is actually in the process of playing or on current world-class games of other top players at all time-controls. His spoof American: "Radio Jan" is nearly as good.
Jan Gustafsson (born June 25, 1979) is a German chess grandmaster, author, and commentator.
Overall he's a very good commentator. And so he was commenting the 2015 Rapid and Blitz Championship, but I'm not sure he was great. The thing that was missing for me was the excitement that Dimitry Komarov was able to bring in the 2013 Championship. As I'm sure Jan is great for classical chess, there might be better commentators for fast chess, for blitz especially. Still, he is very good.