I'm with Wild on this one. I've known and worked with several & they're just like any other cross-section of people. Some were great guys- more concerned about sending only righteous cases up than you'd ever dream, if you didn't know them. My favorite flat refused to submit a case on an old man who had a felony bad check 20 or so years prior- and got checked by a game warden while bird hunting.
I crossed swords with another agent some years ago, who felt compelled to try and intervene on behalf of a very active house burglar (and a damn little gun thief, to boot) I had worked six months to catch- so said burglar could help him with 'gun cases' across state lines. Probably wouldn't do for me to run into either of those guys again.