I am a newly qualified secondary school teacher. I want to make a bid to our head for a prototyping machine for my students projects. I was attracted by 3d printers learning about them on my course but they are a bit outside our budget and I’m also worried about running costs...

I saw the Rapman at http://www.rap-man.com/rapman3d.htm
it is a lot cheaper than the dimension machines...
does anyone know if it works well, is it easy enough to build?
Is it cheap to run?

I also saw the Studiomill Educational CNC machine at http://www.corerobotics.co.uk/CR_Studiomill.html which looks a good CNC based solution though a lot more expensive than the Rapman, has anyone used it? With CNC I can use any material in the workshop but might CNC be more difficult to use?

Which will provide the best educational experience for my students CNC or 3D printing?

Cheers, Ian