He's a coach, not a commentator. Imagine Kirk Ferentz trying to call a football game, and every time the color guy says something, Kirk brings up a story/comparison from his time at Iowa... Just like he does in interviews. Same deal here.
Calhoun is simply a case of an extremely successful ex-coach who still loves the game and wants to be around it. Works out well for both him and ESPN, who is getting a big name. While we may find some of his ramblings annoying (the 3-4 Allen/Gordon references brought up), he brings a unique perspective, and one that we don't often hear in the sports world. I enjoyed his discussion of some of his interactions with officials, the rules, how everything has changed since his early coaching days, etc.
The voice is unfortunate though. It's annoying. However, I was able to understand everything he said.
Better than Vitale, and better than Dakich.