Bartozs, I am running a school http://www.artphotoacademy.com, which offers both online content and offline live events (workshops, lectures and short intensive courses).
Events Maker is perfect for scheduling and announcing offline events, however, because there is no built-in capability to capture information about people who sign up, it is nearly impossible to track those who plan to pay at the door. Another thing is analytics, which is impossible, as Event Maker does not keep history of students who signed up.
So, this is what would be great to have:
1. RSVP system where people can sign up for an event, and their info collected
2. For people who already registered on a site, one-click signing up
3. Ability to tie PayPal buttons to tickets. This one is really easy, as all it needs is a field where a button code can be pasted.
The last thing, which is not related to RSVP issue is that event templates do not recognize widget panels correctly. The left panel appears on the bottom of a page, and the right panel is not visible at all.