Ken at Crim Law makes federal criminal practice sound pretty horrible, particularly in his description of the "federal defense game" in this post.
I'm ashamed to say that I have avoided federal criminal practice thus far in my career, for no particular reason other than that the federal judges apparently can't or won't appoint me to defend indigents without my consent (as sometimes happens in state court) and it would take too much work for me to avoid looking foolish in criminal cases (as has happened in state court, most recently a pro bono case over on the Tennessee side).
The closest that I ever came to getting involved in a federal criminal case was one day when I was in the hallway at the federal court in Abingdon as Judge Wilson was walking the opposite direction talking to someone about how he needed to find more lawyers for some case that very afternoon, and as I passed him, he said something like, "Steve, how would you like to be on the court-appointed list for this court? I can appoint you to a case right now." I don't remember whether I made some reply or whether I just jumped out the nearest window.