I haven't seen Bobrow playing in a real match, only in his videos where he is just goofing around and having fun, so I may misjudging his real level. Besides his playing level, what matters is that he is an excellent and funny commentator who helps the viewer understand the game and its tactics and gives a lot of interesting information.
I can't compare him to Richard Prause because I haven't really heard him.
I stand however by my conviction that not everything about the game is a matter of playing level. Some players have an innate understanding of strategy, tactics and identifying opponents' weaknesses which may be far better than other players of higher level.
I believe that Bobrow is such a case and that is what makes him an excellent commentator: When he watches a game, he is able to identify the tactics employed by each player and present it to the viewer.
On the other hand, Riley and the other guy they may have enthusiasm but they only have a superficial knowledge of the game. That's why their comments are like "What a great shot this was" etc. They never analyze tactics and strategy. That may be enough for regional tournaments but for WTT Tournaments we need more commentators like Bobrow.
PS If you want to take an idea about Riley's level, you can see him playing in this video which seems very recent.