You've finished your final draft. You've had friends and fellow writers provide feedback. Your manuscript is as polished as you can make it...so do you start sending it out to agents?
No matter how much I edit my book I still doubt that I've done everything that will make it sparkle in an agent's eye (and I work as an editor for a living). I'm at the stage where I'm debating whether to enlist the services of a professional literary editor, which I've done once before, but the process can be quite expensive. My previous editor has turned literary agent, but I've found a few good leads for future editors from some agent recommendations.
Have any of you used professional editors before? Would you do it again? Did you feel it made a difference when showcasing your work to agents?