We were the first school in North America to install an Epson BrightLink Interactive Projector. It's been great! It's easy to install and use and has an amazing, bright image. Interactive surfaces (whether a board or a projector like the BrightLink) can be a great way to involve students in the learning... when used correctly. That part is teacher training, though, not the board or surface's fault.
When considering a solution for interactivity, two of the biggest things that our school district had to keep in mind were cost and quality. At about $1800 for a 96" surface, the Epson BrightLink packs a lot more bang for the buck than a comparably priced all-in-one solution from Promethean or SMART. The fact that the BrightLink can be adjusted and also project onto any light-colored surface means that you don't have to worry about removing (and losing) additional whiteboard space.
The quality is the other important issue. The ultra-short throw projector on the BrightLink is a beautiful image. It is far brighter, sharper, and more accurate than any of the DLP projectors that come with the usual all-in-one solutions. In our digital age, visual literacy is important... and color accuracy and clarity are essential aspects of visual communication.
RM Easiteach, the software bundle of images and flash activities that the BrightLink can come with, is easy to use. It's not as polished as the SMART or Promethean software, but very few of our teachers take advantage of those tools on our Promethean boards.
We have an additional 32 on order, so we are eager to implement the BrightLink in our educational programs.