This plugin is really good. I think that is the only plugin for appointments that writes the appointment in your database and has all the features you need to design an appointment system. You are no dependant of other Webs.
New features in the last version are really usefull, and the traslation has been included. Great!
Congratulatios to the development team. They have others plugins really good, as Calculated Fields Form, for instance.
I have bought the pro version of appointments and looking forward to buy the pro version of Calculated Fields Form.