I've been playing around with these recently and they're amazingly good. I've had them hooked up to Battery and BFD and jamming around with them is brilliant fun.
For £229 it's a bit of a steal and you can buy an additional set of pads for around another 30 quid. The only real downside is that the kick pedal is a switch (so no velocity).
I'm considering keeping hold of them just 'cos they're a brilliant laugh and inspire a heck of a lot of creativity. Also a darn sight cheaper than most other electronic kits. http://www.decks.co.uk/products/dj_production/ion/ied01