If you are applying to several different schools using one generic statement will be easily recognized and just as easily dismissed. WHY _ because you will be seen as not making an effort sell yourself to this particular school, low effort equals low interest to admissions representatives. Remember the admission committee will likely view thousands of these statements from qualified candidates and they will spot a weakness, flaw or lack of attention to the process in a heartbeat. What you don't want to do is give this committee an easy excuse to dismiss your statement and application.
Remember, your personal statement is 'personal' in nature so it is in your best interest to be sure that all the information you provide is in fact your information. By starting with one sample and taking some ideas, then moving on to another and taking additional ideas, and so on, you allow your true self to come out in the finished product and this will give you the best shot at gaining access to the school of your choice.