BoardWizards has an excellent CBPS case portfolio, and also all selection fields match the actual exam perfectly. The diversity in case presentations will get you comfortable with developing an effective workup process to maximize the information gained from the limited selection on the actual test.
This program really aided me in becoming board certified on my first attempt. It was very helpful in familiarizing myself with the layout of the test and that saved time.
Of all the services I used to prepare for boards, this platform most closely mimicked test day.