can a private attorney get a lower sentence for someone than a public defender can?
No one can guarantee what the outcome of a case will be however when you hire a private attorney typically they can devote much more time to you and your case because their caseloads are significantly smaller then a public defender. Just like everything else they are good and bad PDs and good and bad private attorneys. You should invest some time in consulting with numerous attorneys and choose someone you feel comfortable with.
It doesn't quite work like that. There are some good public defenders and bad public defenders. There are some good private attorneys and some bad private attorneys. Public defenders are actual attorneys.
The problem one faces with having a public defender is that a PD's caseload is huge. While you might have a great PD, they don't really have the time to give you and your case the attention you feel you deserve. Private attorneys do have a lot more time to devote to your case and so it is reasonable that may spot issues in your case a PD wouldn't. But the hiring of a private attorney is no guarantee of an outcome. The nice thing is that unlike a PD you get to choose your private attorney. I suggest you meet with several different lawyers and decide for yourself which is the best fit.
Hiring a lawyer versus "using a public defender" has its pros and cons. One of the most significant pros of hiring a private attorney is that their caseload is usually significantly less than that of a public defender. This usually means that a private attorney can personally spend more time on your case and that may positively affect the outcome of your case. One con of hiring a private attorney is that many private attorneys, without previously working for the Public Defender's Office or State Attorney's Office, lack the trial experience that a Public Defender may have and that may not be as beneficial for your case. So, in deciding whether to hire a private attorney or not, your decision should be based on a variety of things. However, since no lawyer can guarantee the outcome of a case, your decision should probably be based more upon the background and experience of the lawyer than any promises made to you by him or her.
As Ms. Glenn said it depends on the attorney. The public defender's office is swamped with cases and are funded by the State. So, a private attorney typically has more time to give each case individual attention and has more resources available. However, there are excellent PDs out there. If you can afford to retain private counsel, you should do so, as the Public Defender's office is for people who absolutely can't afford a lawyer.
I have high respect for the attorneys who struggle in Public Defender Offices across the country. That said, if you can afford to hire a qualified private criminal lawyer, I believe you will be better off, if for no other reason you will have an attorney with the time and inclination to thoroughly advise you and keep you informed. Interview two of more (most provide limited free consultations) and see if you can locate one that has the requisite experience and skill and with whom you are comfortable.