As the son of two career public defenders and a public defender myself for over eight years, I have great respect for the competency and mission of public defenders everywhere. In most jurisdictions, the public defender’s office is the largest criminal defense firm that does the most litigation and trial work as an office, and they set the tone for how cases are resolved and what cases are worth.
It’s important to note that in order to get a public defender, you need to submit financial info demonstrating a lack of ability to pay a private attorney. People who are able to afford private attorneys should hire private attorneys, and should not overburden an office that already has large caseloads and is intended to represent the indigent. Accordingly, the rest of this answer applies to individuals who qualify for a public defender, but might be able to get some money together in order to hire a private attorney.
When you apply for the public defender, you are appointed an attorney. While it is true that public defenders are some of the best criminal defense attorneys there are, you don’t get to pick your attorney, and not every public defender is equally motivated and competent, and some have very large caseloads. While many public defenders office have rigorous hiring standards and train their deputies to handle tough cases, newer attorneys are often put into a misdemeanor assignment. If you pick up a alcohol-drug combo DUI, for instance, you are often assigned a newer attorney that may be excellent and capable, but may also simply lack significant experience trying cases like yours, and may not have read the studies that the DA intends to introduce at trial
When you hire a private attorney, you get to interview them first and only hire them once you feel it’s a good fit. If you don’t like the work your attorney has done, you can fire them and go find a new one.
Applying for representation by a public defender may be the best and most cost effective choice for some people in some cases, and if your case is the kind of case that is pretty straightforward and requires minimal work, I will be honest if you if I think hiring an attorney is a waste of money.