Source: http://ictforeducators.com/2012/09/the-perfect-iwb-using-apple-tv-ipad-and.html

For the most part, Splashtop Whiteboard or Doceri is still a great option to get the key features of an interactive whiteboard for a fraction of the cost. The main drawback, however, is that you are controlling your computer from a mobile device using these apps. You are not projecting the content directly to the projector or TV. 

Our school has installed a number of Epson interactive whiteboards which have largely been a waste of money due to the limitations of the software that comes with it. We began testing out the SMART Board which is a far superior option but is still a very expensive investment which I am not convinced is worth the cost. 

By Mr. Kaustubh Kulkarni, Director - Fusion Softwares & Systems Pvt. Ltd.