The key differences between the UPSC and State Public Service Commission examinations lie in their scope and focus. UPSC conducts exams for central services, while state commissions focus on recruitment for state-level positions. The syllabus, examination pattern, and the number of attempts allowed often differ, with UPSC examining a broader spectrum of subjects, including national and international issues. Additionally, the selection process for UPSC is more competitive, attracting a larger pool of applicants aspiring to secure positions in esteemed central services.