We are replacing our last 2 cambridge boards with smartboards this coming year, so will have 4 sitting around doing nothing.
Teachers hate the cambridge boards, as the pens are useless and chew through batteries. Smartboards are much more suited to an education environment IMO.
Our Hitachi's are slowly being replaced by the SMART boards (cant remember the model number, but it's there all in one beast). Had issues with two of them, can't complain about the support though. They were here straight away and sorted the problems (for one of them the engineer just gave us a new projector- without any fuss about it either).
My primary school has one of those snazzy ActivBoards that has height adjustment, they're really quite nice!! They look alot nicer than the SMART boards, however, I like the easy of use you get with the SMART.
Just two throw in my two penneth... after a bit of investigation, I chose GTCO Calcomp Interwrite boards.
These boards are cheaper than Smart/Promethean and the software is very good IMHO. The software is also available for Windows (as an MSI that just deploys!!!), Linux and Mac!
Smartboard all the way ,,,, we have both a mix of smartboard and promethean -- and the smart boards have never failed, where ive had countless troubles with the promethean. We only purchase smarts now.