I just picked up my Professional Scrum Master I (PSM I) certification from scrum.org. It's a fair test. I encountered several "best answer" and "all that apply" type questions. A passing grade means correctly answering 68 of the 80 questions in 1 hour. I reread the Scrum Guide and took the Scrum Open Assessment to prepare for the test. For those that are interested, the certificate can be verified here. I'll need to start planning out my study schedule to prepare for the PSM II certification.