A school which is under funded will not have access to the same resources a properly funded school has. Many schools rely on local property tax however, low income schools are surrounded by apartments or other property that will not generate that property tax. In a poorly funded school, students' access to technology, school nurses, aides, tutoring, sports, and so forth could be limited.
The class gap is slowly but surely widening, racial diversity is becoming a sharper and more distinct issue, and LGBT students are still fighting their battles. Whether it be inequality in a social sense (aka bullying or slander) or in an economic/political sense (schools in poorer areas are underfunded and not supported) inequality is an issue most people ignore and don't realize is occurring.
No, because we do not have problems with racial inequality, and our education sector focuses strongly on harmony between different races (we have Racial Harmony Day). People who cant really afford to go to school are often subsidised/aided by the Government. People here are generally equals, although to some extent children can be laughed at for being poor, which can lead to some children rejecting/afraid of school.