We have worked hard on this calendar. We have not updated a free version for quite a while but as soon as our premium version gets it's last polish, the free one will get attention too.
But if you want to have our premium calendar right now then we will give it to the ones who would test, give constructive feedback (locate bugs, logic problems etc.).
New version has also a form builder inside. So now you could create different forms for different events.
Contact me to get the plugin for testing: firstname.lastname@example.org