I've just graduated from a federal agency's academy. I'm still terrible on the radio sometimes but a few of my instructors know good agents with stutters. Most of my commands are pretty decent though. So I'll let you know if its a detriment out in the field. I report in a few days. And I'm almost positive for all the state/local agencies that I applied for, I was denied because of my stutter. My interview was pretty bad for one and I was pretty far into the process til I got to the interview. Another one never called me back after the polygraph and another denied me after the interview although it was decent.