Sorry for the extremely late reply, Jef.
Producteev had to disable some features when they did a recent major update. They say that Gcal and the like will be turned back on soon, but they have definitely been delayed.
This isn’t a syncing system, it’s a workaround. If your notes aren’t coming through, check to see that your syntax in Evernote is following the Producteev mail2task syntax to add a note. It is possible there are bug issues as well, related to their recent update. If all else fails, contact their support — they are usually pretty responsive, in my experience.