If you are looking for a component to handle public registrations (without requiring users to login), then this one works very well out of the box. If you're wanting something for private events (which require a Joomla user to be logged in to register), it also works well, however logged-in users must enter their name & email each time that they register. We were able to work around this by using CB database tables to populate all required fields (nice feature!).
As I see it, this product's main competitor is eventlist by schlu, which I have used extensively in the past. Unfortunately the downfall of eventlist is that it can only handle registrations from registered and logged-in users, which ERP excels at.
On the whole, I give Event Registration Pro five stars. Very happy here.