I have to admit, that I prefer Obie to Geffner, but neither compares to Trup.
O'Brien is, as I have said before, somewhat out of scale to the intimacy of radio. In addition, sometimes he says things that show that he might be a little, uh, shallow.
For example, in Saturday night's game, O'Brien described Jacoby Ellsbury's speed in beating out a grounder for an infield hit.
"He went down the line as if he was a cannon", said O'Brien.
I think the proper metaphor is that he looked like he was shot out of a cannon. Let's face it, cannons don't go down to first base very quickly.