Is Simivastin As Effective As Crestor In Treating Elevated Cholesterol Levels?

My md prescribed Simivastin (sp) instead of Crestor because I wanted something more cost effective. 0 copay instead of $95.00 copay for Crestor. What is the difference in efficacy. My cholesterol levels are exceptional at this time. I had no problems with side effects of the Crestor and hope I won t have any problems with the Simivastin. What is your opinion?