These two reports for Admins are very helpful not only to see how many registrations you have for an event (on the Summary) but also to help you troubleshoot when someone has a question about his registration or a problem registering.
The Registration History is a list of every registration whether it was ever completed or not. That page, which is actually a registration search page, has various filtering options as well, which will help you find a specific person’s registration. You can even filter to find only registrations that originated from the TouchPoint mobile app!
Whereas the Registration History is a list of every individual registration, the Registration Summary is just that – a summary of registrations by Description. The Description is actually the name of the organization used for the registration.