Taking classes would have been my preferred method of earning CPE credits for maintaining my CISSP. The problem is the large number of CPE credits required to maintain a CISSP. Very few companies I know are willing to invest that much $, or time away from work, in their employees.
CISSP is really one of those certs that's meant for [u]full-time[/u] security people. Earning one requires documentation showing years of prior experience, lots of preparation for the exam, and a score of 80%.
Security was less than 50% of my position, and it was just too difficult for me to keep up with the CPE requirements.
They also changed the number of CPE's required every three years, to so many every year of that three year period.