Best are those who explain to the general audience: Tim De Ruyter, Tony Robles, Mike Yednak, Earl Strickland once he is not talking about himself, Alison Fisher, Imran Majeed, Jim Wych (sp) ... I also like Mark White for his high energy commentary.
I don't like commentators who talk to each other in the booth at their own level of knowledge even though they are very knowledgeable. Sometimes I cannot understand the shots they are calling even though I know pool a bit. They need to make better use of telestrators.