I've been using Promethean activexpression
http://www.prometheanworld.com/server.php?show=nav.15997
I only teach A-level but my students still love them after 4 outings
I think they have a great potential, with the usual rider, if used well
Basically each kid has a wireless hand held device a bit bigger than a mobile. They can do multiple choice question or free text response or all the other usual suspects like a number or rate on a scale
the software is fine now but we got lost in a maze of old versions of software and compatibility issues
The softwaregives the teacher good feed back. Who answered what and when, all the data can be exported to excel