I used OSP's exam simulator. The exam questions were easy because this simulator covers as many scenarios as possible. Once you understan the scenarios, questions in the exam become very easy to answer. I did not use any other simulator. But reviewed other Free qusetions available on the internet
Here is what I did: Listened to the complete Agile Prepcast (Twice). Then worked on the PMI-ACP Exam Simulator and answered every single one of the 480 questions and took all the 4 exams. I was able to answer a number of questions with ease.
I also read Crowe's book to get a different perspective.
I strongly recommend everyone to follow this plan for success.
Training for Project Management Professional (PMP)®, PMI Agile Certified Practitioner (PMI-ACP)®, and Certified Associate in Project Management (CAPM)®