I highly recommend this extension. Besides, the commercial version has a very reasonable license fee. The support is well-organized, using an easy-to-manage Helpdesk and they promptly respond to every question, offering a huge amount of help and knowledge. My problems were identified and solved within minutes.

The layout of the Book is well-chosen and it is easy to manage within the BE.

It is a brilliant tool, but as a non joomla-specialist, it took a while before I understood the system.
I closely followed the tutorials but what really helped a lot was looking at the actual developer's site (www.chronoengine.com) and the demo form. Then I accessed the source code and copied that into the chronoforms environment.... I slightly edited the HTML-code and it is now perfect.
Overall highly recommened

DT Register is an excellent software product that allows you to manage your events very efficiently. The joomla interface is easy to understand and on the DT Register website you find good tutorials.
If you have further questions, you can also directly contact the software developer. My questions have been answered within minutes!
Highly recommended.