EDITED TO ADD: Pseudosu asked a good question (thank you!) that made me realize I didn't exactly clarify -- the comments and track changes I mention below were done by me (not my agent or editor, although many of the notes are reflective of the line edit he sent me, as well as our brainstorming session).
Number of comments (via Track Changes) made in the manuscript: 127
Number of passes made so far: 4
Grammar mistake made most often: Commas. Grrr. I hate those little f-ers!!!
Most humorous mistake thus far: 'disease infested', was 'disease invested'. Heh.
Samples of some of my comments: "Get real." "Ah! That explains everything!" "Ask Ed." (okay, so that one might be used more than once.). And my personal favorite: "Not sure. Thinks this reads better to eliminate the two idiot lines and go with the other line . . ."