Believe me, the most common emotion on the debtor's behalf will be embarrassment at having to be pursued by a 'specialist' to make good on their debts. Even so, as a precaution we always tell students to use a business name and a post office box for all of their correspondence. This will protect your anonymity while maintaining a professional image. It is unlikely that you will find any competition. Keep in mind that collection agencies are NOT any direct competition to you.
Collection agencies tend to focus on pre-judgment debt.
They do this by sending dunning letters and making annoying phone calls to the debtor. The only judgments that collection agencies usually collect have been awarded to their existing clients. Your competition, should you find any, will be other judgment recovery companies. Most attorneys specialize in one area of law or another. Only a small percentage of those attorneys specialize in collections.