mal wrote a review of Mammut Smart Belay Device on September 12, 2011
I've shown this to many people who then went ahead and ordered one. I find it puts many (especially those new to lead-climbing) at ease when climbing, knowing they can count on the equipment to stop them.
Takes a bit of getting used to, but SO much better than a grigri... I've seen people say it doesn't always lock (or not completely), but I've never had it not lock on a fall. Highly recommeneded.