From teachers' point of view, working for the state has many financial advantages; a good retirement system, a decent wage that can be supplemented during the summer, good benefits such as free health care insurance, and, in some states, a strong union movement that protects all, even the incompetent ones. Public schools teachers are opposed, obviously, to the voucher idea which would allow parents to place their children in private schools. They (the parents) are often unaware that private schools don't have the same stringent requirements compared to public schools, and that the so-called government vouchers will not afford the high-end establishments which sometimes have annual fees between $15,000 and $30,000.
Experts in education generally agree that the best private K-12 schools are those run by a religious order. Among these, the Jesuits have become famous the world over as very strict and efficient school mentors. Or course, non-catholic families will shun such learning centers which promote a specific religion. The rest of the private schools, the non-denominational ones, have the reputation of forming elite mentalities in their students. Some are well-known as diploma mills, where the academic requirements are less rigorous to say the least.
As a parent of K-12 kids, I would seriously consider public rather than private schools. There are are excellent public schools, as there are excellent private ones. The main difference is that the first is free, as they are funded by our taxes and government grants. Music and athletic programs are also much larger in public schools, allowing children to chose among a wide variety of extra-curricular activities. The other consideration often mentioned by concerned mothers is personal safety. Some people say that public schools are not as safe as private ones. While it is true that students may face some unsavory characters in their schools, it is a fact that school districts are giving close attention to the matter. District police and school monitors constantly roam the halls to ensure students' safety. Cameras are placed at strategic locations to detect any unwanted behavior.
It is also a fact that public schools' teachers receive better pay and benefits than those in private ones. This allows them to attract better candidates and suffer a lower rate of rotation. Public schools' teachers' training touches on all fields of education during the whole academic year. We know that bad teachers are found in all areas, whether private or public. School districts are making a decisive effort to root out those mentors who haven't shown the dedication and vocation needed to motivate students. Another caveat for private schools is the fact that they don't have to accept children with special needs unlike public schools. If your child requires special help and treatment, such as speech impediment, loss of hearing, or learning disability, chances are that the private school will not accept him/her.
Some studies show that private schools outperform public ones in standardized tests. Remember however that private institutions select the best students, while public ones take any child whatever their skills or intelligence levels. However, other studies confirm that public schools do very well, taking into account that they serve the general population and not a specific privileged segment. If I want my child to be prepared to confront life after high school, public education is by far the best tool to do so. Let's not forget that reality does not consist of academic standardized tests; we must be ready to face any challenge and adapt quickly to changing circumstances. Public education does an excellent job in that regard.