Hi Christina,
I'm unable to pay the subscription fees over at their "paid support site" but I followed the instructions to the letter when installing their component.
The test site I'm installing to has latest version of Joomla!, CB, JACL and other components. The hacks they give you to complete the installation are contained in a file called hacks.txt. I implemented those hacks and began getting errors in the back end (administration area) of my installation.
Since I can't browse the forums at their support site, I wasn't able to determine why the hacks.txt instructions caused errors.
That's all I can report for now concerning AEC.
I, too, have been following the various developments of paid subscription components. I've had luck in the past with aMember, who actually did manage to integrate adding paid registration people into groups in Joomla, but that was a few months back.
I don't have any knowledge as to whether Alex (aMember) was able to keep up with the development pace of Joomla and JACL, but I know for sure at the time, you could not use CB if you used aMember.
Hope that helps somebody...