This class works well straight out of the box. However I needed to make changes:
The tar file was in Norwegian and I speak English. Some kind of language facility would be good (eg: all messages in variable form, with variables accessed from a language file or array).
The email subject, rather than being a constant could be a variable, and swap with the message that gets displayed on successful completion of submit (this->sendText). I can use the subject to tell me where the contact message originated from (eg what site or part of site).
Overall then, this is an excellent class with good examples and easy to understand and change