I have installed this on my client's site and it worked like a charm at first try. However, after a few months, schedules are not displayed anymore. After trying to look at what caused it, I asked help from the Forum. Immediate help was provided to me and some tips on how to look for script conflicts. We found out that one of the extension that was installed installed after GCalendar caused the conflict.
I'm rating both the extension and the support team "EXCELLENT".