The personal statement (or statement of purpose) is your introduction of yourself to the application reviewers. This brief statement (generally one to two pages) should communicate your abilities, accomplishments and goals. It must also show us your writing skills, including your ability to present yourself and your ideas concisely. It should show your commitment to and motivation for graduate school based on your history. It should have a positive tone, be honest, and professional.
This is your chance to shine, to stand out from among the hundreds of statements that the reviewer is reading.
It is crucial that you get some honest critiques on your statement before you submit it to the school. However, the voice of the statement should be yours. Remember, if you are invited for an interview, the school will expect to meet the person who wrote the statement. Although you should not have to rewrite your entire essay for each school/program you are applying to, it should be tailored for each program.